The Stovebolt Site Forums The Shop Area The Electrical Bay custom wiring?

hey guys,
im wondering if there is any complications with making a custom wiring harness for my truck. my dad is an electrition and he has LOADS of wire of all gauges laying around, and i was wondering if there was a special wire used in these trucks. me and my dad were thinking about just following the wiring diagram in our shop manual to re-wire the headlights, turnsignals, guages, ect. with the wire he has.
do you forsee any complications with us doing this?? am i making sence??

it should be stranded instead of solid like house wiring

bmxinvasion,

I think it's a splendid idea. I did almost the same thing with 'electrician' wire.

If your dad works in a industrial or commercial environment, he will probably use a THHN or THWN insulated wire. This is good tough wire but isn't quite as flexible as a wire you would find at a true automotive supply house.

It's not a big deal...I sure would recommend doing it, especially if he were to join in the project. Good luck.

Stuart

so what your saying 47chevy6400, is that i should try to use stranded wire instead of solid wire? im sure we have that around here.

well does anyone know what gauge wire should be used with the different components? my dad is asleep now, so i cant talk with him to ask him this. btw, its a 6v system

The stranded wire would for some of your wiring. However the wire from the battery to the ammeter is 8 or 10 gauge which is not common for ac. Also the headlights call for 12 gauge which is possibly in your inventory. The wire from the Generator to the generator to the regulator is 8 or 10 and the wire from the regulator to the horn relay is 10. The wire from the regulator to the ammeter is also 10. I can scan and email or fax a wiring diagram which is essentially the same except GMC is positive ground. Most of the stranded wires such as thnn are oil proof.

I made my own harness. It was pretty easy and a fun job. When unsure of wire size, lean towards the heavier side. You can never go wrong with larger wire, its just a little harder to work with. With 6 volt battery cables, go as big as you can 2/0 or even 3/0. Use a lot of heavy well grounded ground straps and you should have any problems. Add a few extra wires for under the dash and a few for under the hood for extras options that may come along in the future, Radio, A/C, electronic ignition...

Joe

thanks crenwelge, but i have a diagram in my shop manual for my truck, i was just wondering what gauge to use. thanks for your help!!

If you have a GM factory manual, it tells you the gauge and color.

bmxinvasion, you can buy the stranded automotive wire fairly cheap if you have doubts about using the solid wire.

we have stranded wire, LOADS of it, and in all different gauges.. and it is free so thats even better!

but i do have this shop manual out, and im looking at the wiring diagram and it shows the wire colors, but not the gauge they are?

also, where is the ammeter located??

thanks!!!

I am looking at a GMC 47-54 maintenance manual. It gives gauges for all wires. If you are working on a 45 the wiring would be very similar. An 8 or 10 Gauge wire from the starter feeds the ammeter. the other pole of the ammeter branches out to the ignition switch, accessories, and head light switch.

Bmxinvasion, the ammeter is the battery gauge, not sure where exactly it is, but it should be there somewhere.

It's one of the gauges on the instrument panel, The one that is marked - and + and usually says amps.

I think it will say D and C for drain(draw?) and charge...

Great dad and lad project and I approve. I wonder if the color of wire and gauge is universal. Also bmxinvasion are you planing on going back original or will you upgrade with a fuse box?

big chevy 3600,
which do you reccomend? is the fuse box expensive?

I don't think it matters, my way of thinking is that if it was good enough back then, it's still good enough today, even if you are going a bit slower.(but that's due to the mechanicals)

It matters if you will be pulling more voltage. If you plan on converting to 12 volt and or if you plan on additional power required extras.
As far as expensive you would need to decide if you wanted to buy a fuse box at a FLAPS and design your own set-up or buy a ready made.
Below are a few links to look at for information. Also Painless Wiring is a simple system and can be found locally at most Auto Zones.

http://www.americanautowire.com/American_Autowire__800-482-WIRE.html
http://www.painlessperformance.com/

I was under the impression that he was going to keep it original except for the bed, which is what he told me.

well jdl, for the most part i am. but if newer technology is safer, and works better, ill go for it.

READ mad electric pages FIRST !!!
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml
http://www.madelectrical.com/electricaltech/brighter-headlights.shtml
read and understand all things first before diving in. Learn about using relays.
you'll have loads of fun and lots of knowledge
KEEP GOOD DRAWINGS !!!!!!!!!!!!!!!!!!

Jim:
Having majored in History because E.E. was much too hard for my "pea brain", I read those two articles between bouts of sleep.
I see after all the testing, Mad Electrical sells parts that will improve voltage and thus improve headlight strength. What type of alternator is original on the AD trucks? If the three wire is better than the one wire, what is the history behind the two alternators?

The way I understand it, one wire alternators are for industrial and farm tractor applications where there are no accessories and the only function of the alternator is to recharge the battery after starting. The use in automotive applications was started by customizers who thought, "Hey, less wires = cleaner look".

One wire alternators are common in large trucks. We use 160 amp Leece Neville. Starting electronic diesel engines is not the problem these days. Running with lights and air conditioner or heater, heated mirrors etc. is what draws the amperage. The transition from generators to alternators was during the early 70's and I never remember seeing anything but a 1 wire alternator used as oem in class 8 trucks and this is a constant high output application.

so just to be clear, most of the wiring is 8, or 10 gauge. i was looking around in my basement and i found a 500 ft roll of 10 gauge THHN stranded wire. i can use this, right? could it be used for the headlights and everything?

also, is a fuse box used to replace the voltage generator ( the box on the firewall with bat gen feild)

If you use the same color and size wire for everything, you are creating a troubleshooting nightmare.

That box is a voltage regulator and a required part of your electrical system. I would suggest you hit the books and educate yourself about automotive electrical systems before attempting this project.

whoa! bmx, look at a wiring diagram and see what gauge was used - I don't know if the earlier schematics included gauge, but the AD ones do - all of the stock wiring is 14-20 gauge, even the 6V headlights only use 16ga I think .... and the thing on the firewall is a regulator, which controls the generator output, nothing like a fuse box ... if you have a 40's manual, read the electrical section, it explains a lot

Bill

Sounds like a three ring circus. I agree with Cletis, without particular wire colors...
I would suggest a small investment in a stock wiring harness might be, in the long run, the cheapest way to go.
Ron Francis sells a pre-war harness for about $400.00. http://www.parts123.com/parts123/yb.dll?parta~partsort
I'm all for squeezing the most out of your buck but not in this case. Just my two cents...

Oh, give him a break, maybe he just typed the wrong word but knows what it is. As I(might be wrong) understand it, bigger gauge doesn't hurt anything, but if you are using the same color/gauge and all, at least mark what it goes every so often.

bigger gauge doesn't hurt JD, but neatness and safety count - a bundle of #8 wires is gonna be real hard to push thru the holes that were made for #18's, and get cut by the metal edges .... and no matter how marked, will be impossible to trace from one side to the other wedged in so they don't move .... there's orignal style harness available for under $200

we're giving him a break by passing on experienced advice

Bill

You know what I was talking about, the "voltage generator"? You have a very good point. BMX, disregard my above post, it'd probably be better to use the correct gauge, and if you can't find any numbers, COMPARE! Unless you go with the wiring harness, which would be easier.

Whether he calls it the "voltage generator" or regulator doesn't matter as much as the fact he doesn't know what it does and he thought he could replace it with a fuse box. Anyone who knows that little about automotive electric systems has no business tackling a rewiring job until he better educates himself.

I'm not trying to cut you down, BMX, or discourage you. I'm just stating facts. There's plenty of material available free on the internet for you to educate yourself on this. Go for it. Good luck.

One place to start is Jolly's excellent website. basic wiring tips

We all have to start somewhere, and Stovebolt is the best place - isn't it?

Ohhh, sheesh, I need to read more carefully.

ha yeah guys i agree, i have no automotive wiring expirence what-so-ever, so im trying to pick up as much as i can. im no where NEAR ready to tackle this job, and i havent done much with it. (by the way, i meant voltage regulator, just a typo) but i still didnt know what it did.
well on my shop manual diagram, it doesnt say the wire gauges, but looking at the one red58, i can (kinda) see what gauges to use.
and im not alone on this project, my dad doesnt know much about wiring cars, but hes been an electritian for 15ish years, so hes going to help me out. once i read more on wiring.

cletis, thanks for the link

wiring diagram i have

red58, should i be able to just follow the gauges on the diagram you showed me?

theres some other wire diagrams on that site, which are clearer. are these truck years mostly wired the same? am i a complete fool

yes, you can use any 6V schematic as a good guide as to wire size [54 back], but don't use one for a 12V truck [55 up], they use lighter wires on most everything ... most critical on the 6V is battery cables, they need to be heavier than the usual 12V cables you find at the FLAPS, use 1/0 or 2/0 batt to starter

no yer not a fool, just need some learnin about some aspects of dealing with the ol rig, and that site has tons of useful info ... the 42 manual actually has some good electrical 'theory' stuff in it that can give you an understanding of the way the whole system works

Bill