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because of cost and a liking to mess with wiring ive decided to do my own wiring. ive found that by making my own wiring harness i will save around 300 to 400 dollars. in order to make sure i dont mess up, ive drawn up three seperate diagrams, one for the engine, lights and options i plan to add. before i start id just like to get some input on what im about to start

here are the links to what i came up with
http://i175.photobucket.com/albums/w124/rockfan1815/new%20wiring/engine-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/new%20wiring/lights-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/new%20wiring/options-2.jpg

feel free to comment, thanks

If you can "mess with wiring" as good as you can draw it looks like you'll have a nice harness. The only difficulty I can foresee would be in the fabrication of the loom.

Don

thanks, im a mechanical drafter so i work with autocad alot. i actually came up with those plans on autocad (2008), they would look horrible if done on paint.

Im going to mess around a bit with the layout. Im planning to mount the fuse box under the dash and run the wires that go out to the engine compartment (aside from the ones that go to the starter and coil) to a quick connection box on the firewall. the connector will be as far to the driverside as possible, the wires will run out along the fender to the driverside light and then to the passenger light. same idea with the rear lights as well.

When done have you considered having the cloth woven around it?

There is a guy near me in VA that runs an antique wiring and supplies business. He said if I had my harness all bundled together and the branches coming off where I wanted he could run it through his weaving machine and make it look mostly original.

Grigg

Chris,

Great looking diagrams. There is so much to see that making it all work 100% will probably develop as you actually wire it.

I don't know how detailed your diagram was, but I have a few questions/thoughts.

Your alternator wiring shows the larger gauge wire going to a fused feed from the ignition switch. The two wires terminating in the DA plug would be marked #1 & #2. Number one would be a smaller gauge, and this is the wired that needs to be switched. This same wire could also go through your little lamp to provide a resistance, AND act as your 'idiot light'...or battery light as you have it noted.

Wire number two from the DA plug would be the larger gauge, and could actually wrap right around and tie into the large BATT terminal.

With all the cool stuff going on with this rig, a nice single wire alternator would eliminate some wires. A internally resisted coil could dump a few wires too!

If you installed one or two firewall mounted power blocks, you could tie your your alternator output to the battery there, as well as a hefty feed for the fan relay.

You have lots of things going on, and it sure looks like you will have fun wiring it, especially with the nice 'blueprints' you have drawn. Good luck.

Stuart

Thanks for the comments, as far as the cloth woven around the wiring, have not thought about it, but it is a possibility.

atomarc, i will most likely wire it the way you just mentioned because when i came up with the diagram, i didn't have the truck here, now that it is, ive noticed that it was going to be wired as you stated


a little story of the truck. it was another guys project, he rebuilt the frame, suspension, steering, motor, trans and put a nova high ratio rear end in it. He sold it to my boss before finishing when his wife bought him a already restored truck (wanted him out of the garage). I just bought it off my boss for 900. All that is left for me to do, is really wiring and assembly. He had already taken care of the body work, if there was any to do. i guess his plan was to switch it over to 12v because it already has an alternator and new starter solenoid.

Ill link to my other thread when i get a chance to get pics and create the thread.

thanks again

do the wire gauges look good, are they the right gauge for what they are running power to. Im getting ready to go and buy the wire and other stuff for the electrical and i want to make sure I get the right gauge for each run.

Up to 05 amps: 18 AWG
Up to 10 amps: 16 AWG
Up to 15 amps: 14 AWG
Up to 20 amps: 12 AWG
Up to 30 amps: 10 AWG
Up to 50 amps: 8 AWG
Up to 65 amps: 6 AWG
Up to 85 amps: 4 AWG

http://www.amplepower.com/primer/gauge/

i found these on the internet and used it as a reference.

Chris,

Have you looked into E-Z Wiring Harneses? They will have a set-up for you mine only cost $185, EVERYTHING is encluded.

http://www.ezwiring.com/

Jake

Chris
wow !! very nicely done
i made mine also.

auhh
that's the fun part.
I'm going to have fun looking at this one,
i hope you consider adding a couple more relays for power items,
ie windows, horn, fog lights, two for elect radiator fan etc??
a fusible link for the alternator or other items you wish to protect. I'm not a fan of a maxi fuse for your whole system, because you can distribute those power items in safer ways off a distribution block w/ F-links
i bought bulk wire @ napa /'flaps'

where do i get /borrow a cad system
kinko's got one???
:p


posted 16 August, 2007 23:54
quote:
I used the old wiring 'paths' as a guild. Either make very good notes or take a ton of pictures, you can't take too many, of the wiring if you are going to start with a 'clean slate'. You may also need to renew the gromments and sleeves at pinch or rub points. If you just pull it all out at once you may not remember where these need to be.
absolutely do this.
also think about what you ''may do'' in the future and add it now. ie back up lights, fog lights, any switches you think of, speakers and/or modern radio, modern cig lighter w/ light, hidden 'kill' button, add more ((grounds- cab to frame to bed to radiator frame to tail end,tail lights)), relays (for at least the headlights & horn). LED dash lights for bilnkers (green), alt (amber), low oil pressure(red) and highbeams (blue). LED taillights.
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=10A.jpg
and a three wire alternator >>>> LED dash light for alt idiot lamp (amber).

i made my own wiring harness (cause the PO started but used ALL red wires.
his whole complete diagram fit on one page of binder paper.
i added 6 relays for the higher wattage uses. a new (10 position) haywire fuse block.
terminal distribution blocks
http://www.madelectrical.com/catalog/cn-1.shtml
http://www.madelectrical.com/catalog.shtml
3 or 4 fuse links (homemade) but are avail @ napa or
http://www.madelectrical.com/catalog/fusible-link.shtml
water proof connect plugs,
molex connectors ... http://www.action-electronics.com/molex.htm#Standard
heat shrink tubing, soldered.
split wire tubing like this ... http://cableorganizer.com/wire-loom/
COMPLETE accurate wiring diagram
just great fun doing this project.
WHAT an education this has been.

[ 08-17-2007, 12:30 AM: Message edited by: carolines truck ]

--------------------

thanks for replying. as far as the maxi fuses, im copying the idea off newer cars. Actually today i picked up a maxi fuse panel and a main fuse box along with about 300ft of wire(might need more)

http://i175.photobucket.com/albums/w124/rockfan1815/PIC00001.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/PIC00003.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/PIC00005.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/PIC00006.jpg

"Your alternator wiring shows the larger gauge wire going to a fused feed from the ignition switch. The two wires terminating in the DA plug would be marked #1 & #2. Number one would be a smaller gauge, and this is the wired that needs to be switched. This same wire could also go through your little lamp to provide a resistance, AND act as your 'idiot light'...or battery light as you have it noted.

Wire number two from the DA plug would be the larger gauge, and could actually wrap right around and tie into the large BATT terminal." by atomarc


for the alternator i was going off this.
http://www.6066gmcguy.org/charging.htm

And what large wire are you talking about? the red wire (labled 6) goes to the battery, the purple wire goes to the idiot light, while also providing resistance and the yellow wire goes to the the fuse box (to excite the alternator) where its hooked to a acc line so it only excites the alt when the key is in start/on. is this correct?

but this is how the po started to wire the alt.
http://i175.photobucket.com/albums/w124/rockfan1815/chevy%20truck/PIC00011.jpg

Chris,

I think the explanation of wire function is wrong on the 6066 site. Wire #1 energizes to give the field an initial charge, then becomes "charged" itself. This is the function that makes the idiot light turn on and off! Wire #2 allows the regulator to keep tabs on the alternator output and regulate it accordingly.

It's possible to have a alternator with a regulator in it that allows single wire operation, so not all is revealed just by looking at it.

The last photo you linked of the previous owners setup would be proper if the wire going to the BATT lug came from terminal #2....it looks like it comes from #1, which isn't correct.

If that wire were moved to #2, and a wire were attached to #1 that was energized when your truck was running (key switched), you would be in business. Any charge light would be hooked in series with that wire to #1.

I'm pretty sure this is how it works. I reference that 6066 site a lot, and he has tons of great info and a great site...I didn't want to come across as "dissing" him as he might have overlooked this item, or I'm all wet.


Stuart

http://i175.photobucket.com/albums/w124/rockfan1815/chevy%20truck/PIC00011.jpg

that's bad news as you know this.
you actually want a little distance from the DA plug wire 12V+ running off some equipment otherwise the alt 'thinks' it's got a full 13.4 volts @ the batt... as the picture shows.

my thoughts are as stu suggested a dist lug run off the alt.
http://www.madelectrical.com/catalog/cn-1.shtml inside the engine compartment where you could run an 8 ga. wire back to the starter 'batt' post which has a 2or4 ga. to the batt. all the big amperage wire would remain in the engine comp. and use fusible links to #30 post of relays.
http://www.madelectrical.com/catalog/fusible-link.shtml
Keep them out of the cockpit! (When Fusible Links burn they often emit sparks and smoke.)
if you use relays the low voltage wires can then safely go inside the cab and the high amp stuff in the engine side.


''Examples of circuits where the Fusible Link wire will be the most reliable short-circuit protection are; *the main power wire to the dash area, *the alternator-to-battery “charging wire,” *power-up wire to electric radiator fans, windows, seats, and other systems where the amount of current flow is a large amount for long periods of time. ''

''NOTES about Fusible Links Only a serious short will cause a Fusible Link to burn–it disconnects a circuit from power just before the rest of the wiring in a circuit would be damaged. Momentary overloads will not burn out a Fusible Link–such as arcing a wrench between ground and an exposed terminal. ''

you are running the headlights thru a 30 amp fuse but have two relays after.
http://www.madelectrical.com/electricaltech/brighter-headlights.shtml
another two fusible links can be used ... one per hi &&& low.
you show three maxi fuses and three fuse blocks.

if you're running a 10 or 12 si alt why do you have a ballast resistor?? as i did not see an HEI distibutor.

please take this as thought..... you have done a great job.
i'm having to re-learn this as i've made my harness but am now just getting to install it. as Stu says it will work itself out as you install/ test all wires and label as such.

http://i175.photobucket.com/albums/w124/rockfan1815/engine-3.jpg

unsure what amp link should be used for the wire from the alt to the power block and for the wire from the power block to the ignition switch.

i also redrew the diagram to show the battery in the stock battery box under the passenger floor.

im using the stock ignition setup, except for a msd blaster 2 ign coil
http://www.msdignition.com/coil_blaster_1_8200_8202_8223.htm
it says to use the ballast resistor must be used for stock point ign setups.

also (not sure if i should do it this way) but ran the wire that goes from the power dist block to the ignition switch right to the ign switch, instead of running it through the fuse box like i had it before

should I still have it going to the fuse box or is two fuses no use?


What makes the fusible link safe/better than using a maxi fuse dist block?

http://i175.photobucket.com/albums/w124/rockfan1815/wiring/lights-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/wiring/options-2.jpg

I redrew the options and lighting diagrams to have fusible links. my question is how many wires can be wired to the power dist block.
currently these are what are going to it
1. alt charge w/ ??amp fuse link
2. ign switch power w/ ??amp fuse link
3. cooling fan power w/ 30amp fuse link
4. head light relays w/ 30amp fuse link
5. lighting power(to fuse box) w/ ??amp fuse link
6. power options power (to fuse box) w/ ??amp fuse link

should i add two blocks and if so, do i run two seperate 8ga wires from the starter solenoid batt post to the blocks?

how do i figure out what amp fuse link to use. do you just add the amps up on that circuit or what?

maybe power block 1:
-alt charge
-ign switch power
-cooling fan power

power block 2:
-lighting power
-head light power
-power options power

if you can think of a better combination, please
post


also even thought it looks like seperate fuse boxes there is only one. I had a diagram that had all the wiring for the engine, lights and options but it was getting to crowded and needed to be split up.


and as far as a copy of autocad, you can get a 30 day trial at http://usa.autodesk.com/adsk/servlet/mform?id=9106363&siteID=123112

to buy the programs its expensive, up to 4k for the full version.

gosh I WANT a cad system for my computer
I knew i was missing out on some cool things.
all my truck wiring diagrams are hand drawn.
maybe it's the cool colors i like. thanks for the link to cad.
great work chris
you have a very good handle on all things electrical. a lot of folks buy harness' but until you design, make and install/ test a complete system shows great pride and understanding.
> this was confusing to me cause of the different amp fuses shown were not the same, so it looked like three blocks.

> I also have two power dist term blocks, one forward @drivers inner fender feeds from the alternator via a short 8 ga. fuse link, (then an 8 ga. wire back to the starter crossing under the rad support in split housing~ everything is in split housing and grommets so hopefully NO elect shorts :rolleyes:
i believe ALL fuse links (i made all mine) should be about 6-7 inches long plus what ever wire and solderless (soldered & heat shrunk) ends, this block also feeds the relay bank, so i.e. all those items listed below connects via fuse links. the fuse links protect each of those circuits separately, then to the second term block one 10 ga. on the firewall outside the cab. @ that one feeds the DA plug sensing wire so the alt gets a different voltage reading away from close proximity to the alt like your PO had .... Hummmmm. the firewall also feeds to my cab ign. switch and fuse panel. from there all things acc. wise feed off the fuse panel. I fed all acc. forward from the forward block and all things @ the main fuse panel and truck rear off the firewall block. kinda keeps things straight. much like what i see on your diagram. everything in split housing. cloth is fine for show. my.02

On my system, i have a bank of relays fed by fusible links. two because of start~up power && I want power to that and back-up ALL the time, for my radiator cooling fan, one ea. ~ Hi & Low beam, fog lamps and horn (dual fiamm type) and one other but i can't remember right now.
relays are cheap, about 5-6 bucks ea. all labeled.
DON'T forget to ground the cab to frame as you have mentioned also the radiator support to frame and frame to cab and frame to bed. in my case frame to inner fenders. ALL very important .
i recently got my truck back from the painter so i'm now slowly installing all this (i have also moved in the last several months). I'm sure some items might change when i get the front clip bolted back on. I'm about to drop the engine back in and then the front end stuff. then wire some more.

maxi fuses have the advantage of replacement made easier by design. pop out - pop in. fusible links are tougher to replace because they may (in my case) be integrated into the wire system. so yes i will carry spares and yes they take up more room in the traveling tool box and IF one fries ms caroline will have a tougher time correcting it. but then again... something else is seriously wrong. I'll get THAT cel phone call. but hopefully NOT
~~~~~~~~
I ALWAYS CARRY A HALON EXTINGISHER
~~~~~~
one source that 6066 uses is MAD ELECTRIC ~~ Mark likes fusible links and his business is wiring::
http://www.madelectrical.com/catalog/fusible-link.shtml
Alan Horath is one of the electrical ?? here and he likes his also.
-----------
18ga. Fusible Link protects 14ga. or heavier wired systems
16ga. Fusible Link protects 12ga. or heavier wired systems
14ga. Fusible Link protects 10ga. or heavier wired systems
12ga. Fusible Link protects 8ga. or heavier wired systems

Notice in the table above that there is always a four number size difference between the Fusible Link wire gauge size, and the size of wire going out to the rest of the circuit. (And with wire gauge sizes, the larger number is for a smaller diameter–as with shotgun barrels, the 20 gauge bore diameter is smaller than the 12 gauge bore diameter.)

The four number differences in gauge size will create the correctly calibrated bottleneck for the Fusible Link to function. Normal amounts of current flow through the Fusible Link do not generate enough heat to warm it up, and normal amount of current flow does not result with significant voltage drop. But in the event of a “full-overload” (“short-to-ground”) problem, excessive current flow through the Fusible Link (bottle-neck effect) will overheat the Fusible Link and burn it out. The protected circuit will be automatically disconnected from power.

Installation and function of a Fusible Link is similar to the “cartridge type,” in-line fuse. But the Fusible Link does not deteriorate or have meltdown problems with constant use in heavy-duty systems, as the cartridge type fuse is famous for. (Chevy began installing Fusible Link wires in the main-power circuits with ’66 models, and of those old cars that are still in use, most of the original Fusible Link wires are still in place. If a Fusible Link burned out then it saved the car!)
-----------
http://www.procarcare.com/icarumba/..._resourcecenter_encyclopedia_lights2.asp

Circuit breakers ::
Circuit breakers are sealed assemblies that perform the same job as the fuse, but in case of an overload, will cut current for an instant. Unlike a fuse, things will return to normal. They rarely go bad but must be replaced with an identical unit should one blow. As with fuses, if a circuit breaker continues to fail, the source of the trouble should be found and corrected.

The main advantage of a circuit breaker over a fuse is what happens when the circuit breaker does its job. When a fuse blows, it becomes trash, while the circuit breaker can cool and reset (to be used over and over again). For this reason, circuit breakers tend to be used to protect high load circuits, on which an occasional overload is expected. Accessories such as power windows or seats which use powerful motors (which might occasionally draw too high an amperage if they encounter mechanical resistance) are good candidates for circuit breaker protection.

You never know exactly where to look for a circuit breaker, but many times, they are located near the fuse box or near the component they protect. On some cars, the circuit breaker that protects the headlights is an integral part of the headlight switch, which must be replaced in its entirety.

Circuit breakers are designed to offer a variety of performance characteristics including three types of reset.

Always follow the ?? OEM's our truck's are not so clear???? recommendations when replacing circuit breakers. Replace only with the same type breaker in aftermarket applications. hard to do in our situation.

Type I -- Automatic reset. Circuit breaker automatically resets after opening, if the fault still exists, the breaker will continue to cycle between ON and OFF positions until the overload is corrected. These devices are sometimes called "cycling breakers."
Type II -- Modified reset. The circuit breaker will remain tripped (in the OFF position) as long as there's power to the circuit due to an internal resistor. Type II breakers can be reset by turning off the circuit, or by turning off the ignition switch. These devices are sometimes called "non-cycling breakers."
Type III -- -Manual reset. The circuit breaker will remain tripped (in the OFF position) until an indicator button or lever is manually reset.
Circuit breakers come in a variety of styles and sizes, and can be mounted almost anywhere. They may be mounted in the line they protect, or plugged into the circuit at the fuse box.

Fusible links and maxi fuses

Fusible links are a piece of wire about 6" long which is spliced into another wire, usually a gauge or two smaller than the wire it protects. Fusible links can be found almost anywhere. Many times they are identified by a colored flag on the link, or by a loop to make it stand out from other wires, and are usually the same color as the protected circuit. Some fusible links may burn in half with no change in appearance, but most are covered with a special insulation that will bubble and char when the fusible link burns.

Fusible links should always be replaced with an original-equipment type.
Most fusible links show a melted, charred insulation when they burn out.

On most modern cars the fusible link has been replaced by the maxi fuse. The maxi fuse is a much larger version of the common standard size fuse (designed to carry the large loads of fusible links) and which have the advantage of being replaced much more easily than the old style fusible link.
Clear as mud but FUN to do

alright, im getting there, it took me a couple min. to realize that fusible links don't have anything to do with amps(well accept for how many amps a certain gauge can handle). it took another in depth study of your last post (carolines truck) to understand and comprehend but i think i got it.

i redid the diagrams again and here is what i did

http://i175.photobucket.com/albums/w124/rockfan1815/new%20wiring/engine-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/new%20wiring/lights-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/new%20wiring/options-2.jpg

i kinda followed what you did on yours. two power dist blocks. one on the firewall (labeled #2) and one on the driver side inner fender well (labeled #1). the fan power, alt., and head light power connect to #1 block and from there it will follow your same routing(going under rad support, following frame and to starter solenoid batt terminal. The ign switch power, and fuse box power wires (2 of them for lighting and power/options) and also the #2 wire from the alt so it gets a accurate reading. that block get power from the batt terminal on the solenoid via 8ga wire running near the firewall.

wow, alot of changes in one day, but id rather make changes on the computer than in the truck itself, by tearing out wires and rerouting.

thanks carolines truck, you've been a big help.

chris
man o man
you're some kinda of guy
pretty cool stuff here as Stu says
there's a lot going on here.
i fed my #2 dist block from #1 dist block by a short 8-10ga wire along the wire path i have set for the headlights & blinkers wires that go along the top of the drivers inner fender loom to the firewall and access wire hole to inside the cab. it's a shorter direct route. whereas you now have the starter feeding block #2. that means you have 3 longer wires both alt and #2 block area wire as well as the tie wire (block #1&2) coming from the alternator /block area to the starter.
or
you have #1 block & alt. wire going back to the starter and another (SINGLE) 8-10ga wire going behind the engine or over the top and to #2 dist block. my alt sensing voltage wire as you know senses the voltage drop @ #2 block also some loss of voltage because it is tied to #1 block as well. my #1 block feeds all my relays, (horn, lights, fog, rad fan, etc) and those are short f-link as my relay panel is on the drivers inner fender.

In your scheme the two block wires have high voltage coming directly off the batt (@ starter) & directly off the alt.
does that make sense. your #1 will have little to add/drop voltage to the sensing of the DA plug @ #2 block
i'm rushing thru this thread but i think i'm saying this right.
it's late for me.
chow

Ps, maxi fuse or fusible link.... 6 of one to some and half doz to others.

so what your saying is to wire the #2 block to #1 which is then wired to the starter. so there would be no wire going from the #2 block to the starter.
is that how i should show it?

yes
the alt goes to #1 block via a 8ga f-link,
#1 block goes to the battery via the starter solonid (8ga) & a big fat wire @ battery.

relays or maxi fuses come off #1
#1 goes to #2 by short route.
maxi or fuse panel @ firewall comes off #2 as well as the DA plug wire back to alt. the voltage sensing now reads everything working thru both blocks, giving the alt. reg a better idea of how much to generate and when.

does that make sense??

did i mention and extra 2 wires
to... the rear of the truck for the back up light.
power to the reverse switch @ the tranny and after you engage the reverse gear, contact makes that circuit follow the wire to the back up lamp(s). i'm using a fog laight there also.
i want to see what's behind me.
cheers chris
i'll go to work and print the drawings and have a look
jim

i think i should have my final wiring diagram, i hope, but dont hesitate to say other wise.

http://i175.photobucket.com/albums/w124/rockfan1815/engine-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/lights-3.jpg
http://i175.photobucket.com/albums/w124/rockfan1815/options-2.jpg

now i just need to buy the fusible links and 8 ga wire and the 2 power dist blocks.

Chris,

Are you open to comments?

Too many fuses...dump the 30 amp fuse in the keyswitch to coil wire.

Dump the 15 amp fuse from keyswitch to DA #1.

Signal lights are tied together with a single wire?

Stuart

always open to comments

so get rid of the fuse i have going from the key switch to the coil and then just connect the DA #1 wire to the batt light and then could i wire it into the guage circuit?

so it should look like this:
http://i175.photobucket.com/albums/w124/rockfan1815/48wiring-1.jpg

Chris,

That will work, but there is still a fuse in the line to the DA #1. It will work OK that way...it's just too much protection is all.

You have a fusible link going to block one from the BATT lug of the alternator, then, in the same line inches away, you have another fusible link.

You have to understand what these links and fuses are seeing and doing. Any protection in the same circuit will see the same load, so more than one fuse or link is redundant.

If you have a device that only pulls 7 amps, you don't need to wire it with 10 gauge wire which you will have to protect with a 30 amp fuse. The circuit should be designed from the device to the wire to the protection...in that order.

Fusible links will protect against catastrophic, dead shorts...boom! You're dead in the water until you can repair it.

Your diagrams are beautiful, but they have lots and lots of "things" in them...things that might not be necessary. It's your truck and doing what you want is the main thing. Make sure it makes sense from a electrical standpoint too.

Stuart

I bought a harness from Brother's trucks. It came in and was manufactured by a company called M & H Electric Fabricators Inc. 562-926-9552 in Santa Springs CA. I liked the harness and it's ease of installation. It was all correct guage and wire colors with extra wiring included for different options. I e-mailed them directly and they will make a harness to factory specs with whatever changes you ask for such as alternator, etc. The wires were not the original cloth covered but a modern style wire. It was no where near what you said that you will be saving. Seems like a money/ time saver to me. Just a thought, G.H.

well where should the wire from DA# 1 be wired to. should it just be wired to the power dist block, i thought it had to be a switched circuit? or should i wire it directly to the ign switch. and where is this other fuse?

and the other fusible link inches away is for the electric fan. the one blue wire goes to the starter batt pos post and the other blue wire goes to dist block 2. neither have a fusible link. the head light power also connects to block 1, with a fusible link. block two gives power to the ignition switch and to the fuse box(via 2 wires, one for the lighting and one for all the extras, all contain fusible links)
the DA# 2 wire also connects to block 2, but has no fuse/link.

do i need fusible links for the wires going to the fuse box?

i like the idea of fusible links, but when should i use them, and when shouldn't i.

before carolines truck mentioned about the fusible links, i was going to have a maxifuse box in the engine bay with 5 maxi fuses. the maxi fuse box would get power directly from the batt. i was going to have it as follows:

1. power to electric fan controller
2. power to head light relays
3. power to ignition switch
4. power to fuse box (constant power for lighting circuit)
5. power to fuse box (constant power for accessories)

this is almost how it is in my daily driver, with a maxi box wired to the batt, and then power to the cooling fan, headlights, ignition/computer and then to the fuse box

premade harnesses are just not the way i want to go. i mainly bought this truck to be a project, i was looking for something to do, and to keep me occupied in my free time, so im in no rush. im actually looking forward to doing my own wiring, i like doing this stuff and am not afraid of messing with electrical stuff. i also feel it will be a good learning experience wiring my own truck.

I fully agree. ...................... it's way cool fun and the knowledge acquired is the best as is the feeling of accomplishment.
~~~~~~~~~~~~~~~~~~~~~~~

i think the DA plug wire should go to block #2
NOT
the short route to the alt output lug as the PO had or what i see in your drawing. if it's @ the #2 block it will sense a drop in voltage that is being used @ both #1 & #2 blocks.

well then im not over using them, i have one for the alt charging wire, one for the electric fan, and one each for the two wires going to the fuse box and to the ignition switch.

now what about DA# 1 wire, should i wire it to the ignition switch so its a switched circuit, with no fuse?

Hey Chris
read this and make a copy for your truck's electrical binder

http://www.madelectrical.com/electricaltech/onewire-threewire2.shtml

How the THREE-WIRE Voltage Regulator Works
(the Turn ON & Warning Light circuit)

With the “THREE-WIRE” alternator model built for cars and trucks, one of the voltage regulator terminals is wired to an ignition switched OFF/ON source. And the OFF/ON circuit may also be used to operate a warning light at the dash. (The THREE-WIRE type can be wired with or without a warning light at the dash. The warning light is an option–not a requirement.)

REMOTE VOLTAGE SENSING, a THREE-WIRE advantage
The other of the two plug-in wires at the SI series alternator is the “voltage-sensing” terminal for the voltage regulator. Through the sensing-wire, the voltage regulator monitors electrical system voltage and makes adjustments to alternator output. The regulator will adjust alternator output as needed to maintain the place where the sensing-wire is routed (at about 14.2 volts). And the sensing-wire can be routed to a place remote from the alternator (downstream).

This “remote voltage-sensing” feature is often a big advantage when running with a factory type wire harness from the Muscle car period (60’s and early 70’s period cars and trucks). Then the alternator output will be adjusted according to what goes on far downstream from the alternator–at the main power distribution junction, which operates the whole car plus charges the battery!

A couple of very important considerations

regarding this factory-original type system, which uses a main power distribution junction, and remote voltage sensing.

(And of course M.A.D. did not invent the system, we are just observing operation of a system that was successfully used for many years. And it is a system that we understand well enough to up-grade, make it friendly for addition of accessories, and make it stronger to accommodate a more powerful alternator operating more powerful accessories.)

(1) The system only works properly when the “battery charging wire” connects from the junction to the battery. There will never be a wire connected from the alternator directly to the battery.

By now the thought may have occurred, that a possible installation could include a heavy gauge charging wire from the alternator directly to the battery. And then leave in place the original wire from the alternator to the factory main junction. Route the voltage sensing wire to the junction, in effort to keep the lights and ignition happy. It’s true that then voltage regulator would maintain the junction at the 14.2 level. However, the fault in the plan is with the voltage drop that will occur between the alternator and the junction. As was previously discussed, the system will compensate by raising the voltage level at the alternator. The problem would be overcharging the battery through the separate charging wire, as voltage at the back of the alternator could be over 16 volts.

(2)The second important consideration of the typical Muscle Car period factory system is the effect of the long battery charging wire (which routes from the junction to the battery). It’s a rare occasion when a little resistance in wiring can actually help us, and this is one of those rare occasions. A small amount of resistance in the “charging wire” leg of this system will serve as a cushion. The amount of resistance will be much too small to be measured with an ordinary ohmmeter, as accuracy of the ohmmeter will only be good to about a plus or minus 0.2 ohm. But the amount of resistance can be calculated after measuring current flow and voltage drop.

To understand how this “cushion” effect with a small resistance at the charging wire works, we must first have knowledge of how batteries behave when being charged. When recharging a low battery, battery voltage will be low, and current flow (amps) to the battery will be a large amount. As the battery becomes charged, battery voltage increases, and it will accept less charge, so charging current (amps) will decrease. Eventually during charging, battery voltage reaches the level of the voltage setting at the charger, and the battery stops accepting all but a very small amount of current.

(See more about how discharged batteries behave when being charged, in photos and captions, at our “RE-CHARGING LOW BATTERIES” page, in this tech section. And see more about special maintenance battery chargers at our BATTERY CHARGING for MAINTENANCE and STORAGE page in this tech section.)

When working with more than a 60 amp alternator, the actual amount of resistance at the “charging wire,” and also the wire from the alternator to the junction, should always calculate to less than 0.1 ohm. The actual amount of resistance will vary with wire length and wire gauge sized used in various models, and the amount of resistance will also change with temperature. (A warm wire conductor will have more resistance than a cool wire conductor.) A new or good condition, factory built harness on a Chevy from the Muscle Car period will have about 0.02 to 0.05 ohm resistance at the wire from the alternator to the junction, and about the same at the charging wire from the junction to the battery.



there is more to read @ mark's MAD Electric site.
above link.
this should clear it up for everyone

Chris,

The traditional method would be to switch (key) that wire, but it doesn't need to be fused.

Your last schematic shows a 12 gauge wire from BATT terminal on the alternator to the power block...then from there with a 8 gauge wire. Can you see this makes no electrical sense.

Keep refining your design, it's looking better.

Stuart

i agree (w/ Stu) it does not need to be fused @ the key switch

me, I'd put an 8ga w/ f-link (this has to carry a potentially large amount of current from the alt @ 'drain' times ) @ the alt big post to the block#1, which then would go (by 8ga) to the solonid starter big post.
then the big 2ga?? to the battery + lug.

14ga. Fusible Link protects 10ga. or heavier wired systems
12ga. Fusible Link protects 8ga. or heavier wired systems

Notice in the table above that there is always a four number size difference between the Fusible Link wire gauge size, and the size of wire going out to the rest of the circuit. (And with wire gauge sizes, the larger number is for a smaller diameter–as with shotgun barrels, the 20 gauge bore diameter is smaller than the 12 gauge bore diameter.)

any NAPA has bulk Fusible wire about $4.00 roll.

http://i175.photobucket.com/albums/w124/rockfan1815/engine-4.jpg

have i got it yet?


thanks for helping me understand this, i dont want to be a pain, but i dont want to toast my investment either.

Chris,

It looks good and you for sure aren't a pain. I'm not sure on this, but I think the fusible link protects the circuit from a massive direct short, which means wire damage. This phenomenon doesn't happen often, especially if you route your wires intelligently and use an appropriate covering.

I can see a link in a big main power circuit, but you shouldn't confuse them with protection for a motor, relay or switch.

I don't know where you intend on putting the fan relay...close to the fan I would imagine. If you brought that wire gauge up to the same gauge as the BATT wire, you could dump that fusible link, as the link in the BATT line would see all activity and protect accordingly.

These are minor tweaks...it's your truck.

Stuart

http://www.painlessperformance.com/Manuals/30103Instruction.pdf

well this is the fan controller i plan on using so i will probably swap the fusible link for the circuit breaker since its supplied with the kit. it still needs some type of circuit protection because its wired directly to the battery through the wire to the starter then to the battery.

the idea of fusible links is good, but im just going to need to keep extras just in case there is a problem(knock on wood there wont be any) but i guess if i wire it right, there wont be any.

Chris,

You're right about the feed from the battery...I didn't figure that one out. I better mind my P's and Q's. Your doing it right!

Stuart