1941 Cadillac Fog Lights

[Jeff Kay CLC#7630]

I am in process of wiring up the fog lights on my 1941 Cadillac.  The lights were already mounted to the car when I got it, but the wires are not hooked up.  Each light has three wires attached to it.  The factory wiring diagram does not show the lights or the wiring.  Does anyone have a wiring diagram showing how I should hook up these lights. 

There is a fog light switch on the dash and it illuminates when I rotate the knob to the right, so I know I'm getting power from the headlight switch to the fog light switch.

Any help would be greatly appreciated.

Jeff Kay
CLC# 7630

[Doug Houston]

Jeff; since the fogs are accessory items on the car, you wouldn't see them on the wiring diagram in the shop manual.

First, the feed to the fog light switch should come from the terminal of the headlight switch, where the front park light filaments waere connected.  Then, the park light wire  will go to the one of the terminals on the fog light switch, where the fog switch light is NOT on.

The wire that will go into the engine compartment to the fog lights will connect to the fog light switch that's hot when the light is on in the switch. 

What happens here, is that the fogs are intended to operate in place of the park lights. The fogs are not supposed to be usable with the headlights on, because together, they draw too much current for the generator to carry.

Now, I'm confused about three wires coming from the fog lights. There is supposed to be only one, as there is only one filament in the fog lights. Looks like somebody has boogered around and put a bulb in them that's not correct.

The question arises now, about if the fog lights are the ones  as supplied originally. You see extremely few of them that have survived the years. I have one set on one of my '41's, and they had to be made from pieces as found.

I once sent a half set to  a metal spinner in LA, to use them as patterns to make new ones. The jerk never returned them, nor ever got in contact with me. He's surely got my parts on his car, and some that he made new.

You probably know that thre were three colors of lenses for those lights. Most were amber, but some were clear (which mine are), then there were red ones, used on the professional vehicles.

[Jeff Kay CLC#7630]

Doug,

Thanks for the information.  The fog light lenses say "Cadillac Fog Light" (or something similar) in raised glass on the exterior, so I'm assuming that at least the lenses are correct.  As for the guts, I'll have to take the lights apart to check.  I assumed that one wire was hot and the other was a ground, but I was not sure on the third.   

[Doug Houston]

OK  Jeff, here's what you should have. There is an outer housing, bolted to the 6 tabs in the fender hole, with a rubber gasket. It will have an armored cable, leading through the hole on the fender to the terminal block. It carries the feed wire to the light socket. The armor isn't waterproof, so water gets into the light assembly. Then, there is an inner light assembly, with a threaded stud, which comes through the large hole in the back of the outer housing. There is a spherical washer,covering the hole, and permitting the light to be aimed, then the nut tightened , holding the light in place. The light assembly is chrome plated, though you only see about 3/8" of it when it's in place. the light has a rubber gasket, sealing it to the outer housing. Both these gaskets were supplied by Steele. They were made from my original gaskets.

The bulb has only one filament; 50  candlepower, if memory serves.

When I readied my outer housings for mounting, I brazed a nipple of 3/8"  copper tubing to the hole. Then, powder coated the outer shell. The sire now passes through the nipple, into a piece of 3/8 fuel hose, into the engine compartment, and there is no way for water to get into the light. I can't recall if Cadillac originally used rubber grommets in the 7/8" holes where the wires pass into the engine room, but I do.

[Jeff Kay CLC#7630]

Doug,

Thanks again for the information. 

I took apart the fog lights last night and found a newer type bulb and reflector.  This bulb had three contacts which connected to a three prong plug.  The light bulb is 6V.  There was continuity between all three wires, so I'm guessing two contacts are for power and one for ground...now I have to figure out which is which.

[Doug Houston]

Someone replaced the socket with one for a pre-sealed Beam headlight bulb. The two contacts on its base are high and low beam. The blb's shell is common, to ground.

Maybe the light will woek OK, but remove the wire that goes to one of the filaments, and solder it to the base ring on the socket, and bring it into the engine room as a geound, to the mounting screw for the terminal strip.  That's what you always need to do on the pre-1940 beadlights. It's almost shocking how mush better the headlights become.