The Stovebolt Site Forums The Shop Area The Electrical Bay Wiring an accessory fuse block

I've looked through the posts about this subject, but haven't seen my question addressed. I bought an electric wiper motor for my '53 3/4-ton and want to wire it into an accessory fuse block which I still need to buy. I also would like to run the heater to this fuse block and the radio eventually. That will get some of the hot wires off of the ignition switch. My question is where should you get the hot wire to power upthe fuse block? I've seen some suggestions not to run it directly from the battery, but where should it come from and does anyone have a photo of a setup showing the wiring from the power source? Thanks.

Rick just bring a 10 gauge wire off the main terminal on your starter (same one battery cable hooks to) I dont se how you would have any issues feeding your extra fuse block from there.
Tim

Rick just bring a 10 gauge wire off the main terminal on your starter (same one battery cable hooks to) I dont se how you would have any issues feeding your extra fuse block from there.
Tim

Rick,

This is sort of a catch-22 deal. The items you want to connect and fuse at your new panel all need to be switched OFF when you turn the key OFF and exit your truck...right! This means they need to be controlled by that same key switch or a relay that is controlled by the key switch.

I would find a nice fuse block, then decide what I wanted to be shut off with the key and what I wanted powered all the time. If the fuse block allows it, you could split your circuits up.

Whatever you do, remember that the key switch and the wires from it have to be able to handle the electrical load you put through it. This is no different even though you are sticking in a new fuse block. If the key switch feeds the fuse block, it will take the total switch load through itself and its feed wire.

If you want a un-switched fuse block, power it from the - side of the ammeter. This is 'connection central' and your meter will indicate any charge/discharge activity with whatever device it attached to the fuse block.

Does this make any sense?

Stuart

Yeh, it makes sense, but I'm just trying to figure out a better way so I don't have to run everything through the ignition switch. Right now I have the normal circuitry plus the radio, heater and soon the electric wiper motor all to the ignition switch. Seems like an awful lot of load on that poor switch, but if that's the standard way to do it, guess it must work okay. It does make sense wanting all of those items to work only when the key is on though.

Rick,

Everything that was switched went through that key from Detroit, but you CAN stick a relay in, switch only it (very minor) and let the husky rated relay contact handle all the oink! Just another option.

Stuart

I like using relays for accessories. When trucks were used to actually work in the 50's and 60's ignition switches and headlight switches burned quite regularly. But in those days, drivers knew how to bypass the switches and make it back to the shop. It wasn't until the 80's that trucks began using relays. We retrofitted our trucks with relays and eliminated a lot of headaches during the mid 80's. Our over the road trucks now have a bank of about 20 relays and we have almost no problems. Hella still makes 6 volt relays. I'm sure other manufacturers do too. You must remember 6 volt draws twice the amperage as 12 volt.

Many of us who are re-thinking the same thing as you are using relays. I have 5 or 6 on my Carolines truck. They are simple to use and you control them by a lower amperage wire to the cab & or IGN. switch. The higher amp. to the feature (horn, fan motors, headlights -- use two relays for hi & lo, heater motors, anything) you wish to power is completed by the relay suppling voltage to it from your stock switches inside the cab and using larger sized wires (when needed). Relays can be used as "remote control switches." It takes only a tiny amount of current to turn the relay ON. But when switched ON, the relay delivers power directly to the accessory. ("high gain" operation).
see mad electric :::
http://www.madelectrical.com/electricaltech/brighter-headlights.shtml
here is a small sized panel that you can fit just about anywhere & can handle up to 8 features.
this one has 12 circuits
http://www.centechwire.com/catalog/panels/pdp3.shtml
http://www.centechwire.com/marketing/spotlight.html

While there are advantages to adding a fuse block and relays, these were not used in trucks through 1955-1st. Good wires, good terminations, correct wire sizes, good grounds (usually screws into sheet metal - prone to corroding) all were sufficient when using standard equipment and factory accessories.

Not all accessories were attached to the ignition switch. The light switch was sometimes used and in a few cases a live post on the ammeter or other screw-post were used for some accessories.

In different Advance-Design years, different electrical attachment points were used for different standard components and accessories, such as a cigar/cigarette lighter (probably the highest power-draw), radio, heater motor(s), electric wipers (in 54/55), and auxiliary lamps. Check out the link above, and you will see a fuse block for a car.

Once again, a fuse block and/or relay(s) are good, but the ignition (key) switch is not the only place where electrical power was obtained in an original configuration.

It depends on how original you want to keep your truck. If staying original is your goal, get a maintenance manual and wire it like it was originally. If you want to improve your truck, use relays. I clearly remember in the 50's if you had a tube type radio and a heater going at the same time the ignition switch got very hot and would quite often fail. Thats why so many Super Deluxe pickups, that is with radio and heater, had aftermarket ignition switches. My first 18 wheeler was a 56 GMC and all the wires including the trailer wires went through the headlight switch. After having several headlight switches go bad in a year I bought 2 Cadilac headlight relays and used one for my cab lights and the other for my trailer lights. That fixed the problem.

I wonder if the 50s ignition switch would have gotten hot if the radio had been connected to the ammeter post and the heater motor lead had been connected to the "dead terminal" on the ignition switch.

I would bet that most installers did not follow the installations instructions, and they simply wired every accessory to the ignition switch.

As stated above, a fuse block and/or relay(s) are good, but the ignition (key) switch is not the only place where electrical power was (supposed to be) obtained in an original configuration.

I wired my fuse box though the Ignition switch no problems so far...I put the heater, electric fuel pump and radio though it I had to many wires on the ig switch...Peter

Unless the accessory is switched OFF with the engine (key), at some point in time it will be left ON and you will end up stranded at Bob's Bar and Grill, or your truck will burn down.

This can be accomplished with a relay, the key switch, or a vow to yourself never to leave the fan motor or the CD player or any accessory running after you turn the engine off and exit the truck...yeah, right.

Stuart

''' While there are advantages to adding a fuse block and relays, these were not used in trucks through 1955-1st. Good wires, good terminations, correct wire sizes, good grounds (usually screws into sheet metal - prone to corroding) all were sufficient when using standard equipment and factory accessories. '''

my 1925 bungalow brick house was originally wired w/ knob & tube, single cloth covered wires and NO HOUSE GROUND....
I re-wired it completely.

me, ... I'll upgrade our truck, thanks

Yes, nothing like comparing apples to onions.

There is nothing wrong with "upgrading" an electrical system. It's just nice to know why an older system is not working properly, especially if it is wired incorrectly in the first place.

Speaking of onions, my 1820 house had been re-wired in the 50s with a 100 amp service, 6 fuses, no ground wires (but it did have a house ground), and as many as 8 lead wires were connected to each fuse in the fuse box. During my complete rebuild, all wiring was removed and upgraded to 200-amp 40-circuit modern system because I remodelled into a new-style house.

But, of course, that is referring to my house, not to a truck that had been improperly wired in the first place.

tim
i did try and look for your house on your site .. oh well

No problem - you can almost see my pickup between the house and garages.

That truck was a fine example of 50+ years of cob-job wiring.

Radios and heaters were usually dealer installed accessories. I seriously doubt If they looked at instructions. It was their intention for the accessories to be off when the engine was off, so they probably did wire them to the ignition switch.

I am glad you brought this topic up. I was replacing the ignition
switch on my 48 3/4 ton, when I noticed that there is no fuse for the ignition coil and no fuse or fuseable link for the big 10 gauge wire that runs from the starter to the - on the ammeter.
In checking the truck schematic from the chevy truck manual for 48-51, page 12-2, there is no fuse running to the light switch and dimmer also. There is a possiblity that one day a fire could happen. A 6 volt battery can light up a 10 guage wire like a toaster. You can keep the wiring original but add a few more fuses. If we put in all this hard work on our trucks, I think it would be wise add some more fuses. Dave in Sandia Park, NM