Posted By: 59ApacheGail Fog light setup - Sun May 04 2014 02:42 AM
Hello All,

I have a very old set of sears fog lights that have only a power wire, they ground via the mount point. I know I need to wire it to a relay then a switch then the power. The problem I have is that I don't know how. I have a 4 prong relay and a toggle switch. I am trying to integrate it into my fresh stock rewire on my 59 apache. Would anyone break it down for me?

I had it wired already without a relay and it caused the old wiring setup to smoke the cab out. The fogs and my wiring is good once I removed all the toasty stuff.
Thanks in advance
Posted By: Jim Sears Re: Fog light setup - Sun May 04 2014 05:00 AM
Find out the power needed for the 2 bulbs, amps or watts.
Make sure the bulbs and the truck are the same voltage.

You don't need to use a relay unless you really want to. You can buy a switch rated for more than the required amps and go direct with the correct gauge wire.

If you want to use the relay, make sure it is rated higher than the draw of the bulbs or you are just adding another weak link.

The relay will have 2 poles for the contacts to switch the lights and 2 poles for the coil to activate the relay.

Power from the fuse for the lights to one side of the contacts, wire to the lights from the other side of the contacts.

Power from a fuse to one side of the switch, other side of the switch to one side of the relay coil. Other side of the relay coil to ground.

Easier to just buy a correctly rated switch and wire from the light fuse through the switch to the lights.
Use heavy enough wire.
Posted By: 59ApacheGail Re: Fog light setup - Mon May 05 2014 04:12 AM
Jim thanks for the info. That was probably the issue before, I had a weak toggle wired in. I picked up a purpose built unity fog light switch with built in fuse. I also picked up a 40amp relay just to be safe.

So if I understand this correctly:

85 would be ground
86 would go from on/off switch to fuse
87 to the fogs
30 to fused power

I am using the same gauge wires I am using for my head lights (i think it is 18?

Thanks again


Posted By: 59ApacheGail Re: Fog light setup - Thu May 08 2014 07:58 PM
My goodies arrived today.

Can anyone tell me what F B T stands for on a Unity Rotary Switch?
F and T are the outer connectors, B looks like it is the power since that is where the fuse is.
Posted By: Steve_H Re: Fog light setup - Fri May 09 2014 12:19 AM
Field, Terminal, Battery. Odd for a relay and lights though. Is this a dimmer of some sort? I just don't know. When I tried to look up the switch it cane back as a delay wiper switch and that is not right.
Posted By: 59ApacheGail Re: Fog light setup - Fri May 09 2014 04:38 AM
Thanks Steve, it was used as a reverse light switch in the 40s. I saw variations that were labeled for heat, parking lights and hazards as well. These are similar to ark-les switches. They are really just a lighted on off switch. I chose it because I could stick it in the stock dash holes and fit a stock wiper knob over top. A fog light switch hidden in plain sight.

So next question is how do I wire that in?
B to power in F to lights T ground?

Posted By: Steve_H Re: Fog light setup - Fri May 09 2014 06:09 AM
An Ohm meter will get the switch functions sorted. B for power sounds right and the switch is going to make a circuit from b to one post or the other when turned to the first position. The ground is through the lights. Sounds like the heater control switch in my truck. But without the resistors. Light in the knob and it looks great at night on hi. Slow speed is pretty dim and both are not visible during the day time. So use the two you need and ignore the third post it won't be used. You might need to ground the light in the knob, maybe. It might just be in the circuit when the fog lights are on. Any way an Ohm meter will help figure what post is what.
Posted By: 59ApacheGail Re: Fog light setup - Fri May 09 2014 05:16 PM
Thanks for the info.
Hopefully I can get this posting photos thing figured out and post my progress.

Posted By: 59ApacheGail Re: Fog light setup - Fri Jun 20 2014 07:46 PM
Ok ...yay for me I figured out how to use photobucket.

I made myself a nice little harness and was just about to set it all up when I realized I hated the way my switch knob looked. I decided to make this lighted knob fit in as if I worked for Chevy in 1959. I am up to my third set so far and improving as I go.
First set was the really bubbly clear red set, next was the solid red set:

Latest set is the clear red no bubbles and they came out a lot smoother and clearer:

The plan is to bore out the back side as the original unity knob with enough space for the inside lamp. When I install I am using the factory throttle hole, getting rid of that unity plate and the bracket.


For the solid red one I will put in a 4 way flasher using single speed wiper switch at some point. Stay tuned for that one.

Still flushing out the gremlins in the tail lights for now as time permits.
Posted By: Roadmarks Re: Fog light setup - Mon Jun 23 2014 03:44 AM
@ 59ApacheGail, Very cool work with the knobs!

Best wishes,

Posted By: Steve_H Re: Fog light setup - Mon Jun 23 2014 06:14 AM
Those knobs look great
Posted By: 59ApacheGail Re: Fog light setup - Wed Jun 25 2014 12:31 AM
Thanks Gents!
Posted By: 59ApacheGail Re: Fog light setup - Fri Jul 04 2014 04:37 AM
Finally got around to drilling out the back of the knob and installing it on my new and improved switch. I didn't get to use a factory location. I could have but would have had to bore out a factory hole in order for the switch to fit. My goal is to leave my truck as pure as I found it so I moved it under the steering wheel and left the unity plate.

The knob works:

This one to keep me honest:


*** As for my previous question about the unity switch prongs

The "B" prong goes to power
The "F" prong goes to the fog lights
The "T" prong I left unused
The switch grounds itself when you mount it, also the harness has a ground built in.

These are diagrams I found on google (they are not my handy work)In case any one else attempts to duplicate:



Thanks everyone for the help!
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