jdshott

Driver's side firewall wiring?

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Pontiac Flathead Experts and Afficianados:

 

In the process of installing the master cylinder of my 1937 Pontiac (2-door touring sedan), I appear to have dislodged a wire to a gold-colored element on the firewall.  I have attached a photo with the gold-colored element circled in black and the disconnected wire beneath it highlighted by a yellow arrow.

 

There are two terminals on the lower side of the gold-colored box .... and I don't know to which of the two terminals the dislodged wire should be connected.  I am also a bit surprised that there does not seem to be a second wire to go to the other terminal on the bottom side of this element.

 

To admit and display my electrical lack of sophistication, based on the wiring schematic in my shop manual, I'm having a hard time figuring out what this gold-colored element is. I had thought that the black box above and slightly to the right of it was the voltage regulator ... but can't figure out what this box is.  Can anyone help clue me in?

 

Note: this is a 6-cylinder engine and much of the wiring has been replaced (probably in the 1960's when this vehicle last ran ...) with red, vinyl-coated wiring.  As a result, I'm unable to use wire color codes to help me.

 

Thanks for your consideration.

 

John

 

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What does your shop manual show?  I have a 37 Olds and it does not have anything that looks like that. The  black box is the regulator.

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Gary:  Thanks for your input.  I've double checked the shop manual and the only things that, to me, appear to be extra "boxes" are the voltage regulator ... which you have confirmed for me ... and the horn relay that is, not surprisingly, mounted on the horns.

 

That, I think, leads me to consider accessories.  To the best of my knowledge, I have three factory accessories: an AM radio, a heater, and a cigarette lighter.  The shop manual shows details of the radio circuitry ... but I find no indication of anything like a relay that might be mounted on the firewall.

 

As near as I can tell, the shop manual includes no details or discussion about either the heater or the cigarette lighter.  I could believe that either the heater blower or the cigarette lighter COULD draw enough current that there might be a relay for switching them on.  Knowing that, maybe I can do a little wire tracing to see if I can figure this out.  In fact, I see that pontiac1953 has just commented that it looks like a relay to him ... so I am going to try to do some tracing to see whether it is connected eitherr to the heater blower motor or the cigarette lighter.

 

Thanks for your thoughts Gary and pontiac1953.

 

John

 

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I would be willing to bet thats a headlight relay, and the little box hanging on it is a circuit breaker.

 

Pontiacs have Guide Multibeam headlights. If it is anything like my 36, the wiring could not possibly make any sense with a relay like that. Do you have a sealed beam conversion? How many positions on your headlight switch?

 

We might need to see that relay with the lid off, and also probably need to know where all the other wires hooked to it go.

 

The regulator looks out of place as well. Does your car have a later generator?

 

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So the wire on the left of your picture, going to the circuit breaker, is the supply wire. Is it going down to the large terminal on your starter?

 

The 2 red wires on the top of the relay appear to be going to inside the car, maybe to the dimmer switch. If that is the case, there should be 2 wires on the bottom too, one to the high beams and one to the low beams.

 

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Bloo:

 

The wire on the left of the box definitely comes from the 6V starter terminal. I will try to see if the top two wires go to the dimmer switch and whether the bottom heads to the headlights. 
 

To answer your other questions:

 

Yes, my car currently has some sort of sealed beam headlights … although I think that I have a set of reflectors, sockets, and bulbs to be able to go back to original bulbs and reflectors. 
 

Yes, my car had some form of newer generator … although I replaced it was a NOS 948-S when I replaced the radiator. I also have the proper voltage regulator to “match”, but the one you see is what was in place in 1968. 
 

Thanks for your detailed posting. 
 

John

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On the original headlight setup, the lenses were different right to left. They had a sharp VERTICAL cutoff on the outer side. The lights were them aimed crosseyed, so that the passenger side light shines up the road where the oncoming traffic is, and the driver's side light shines on the lane ahead and the ditch. When you beam down, only the passenger side dims as it is the only one aimed at the oncoming traffic.

 

They may have used that relay to change the behavior when they converted to sealed beam. Sealed beams have the same pattern both sides and aim more or less straight ahead. Both sides need to dim.

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