VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Headlight wiring

I am finally getting around to completing the installation of the new wiring harness I started a couple of years ago. I am presently working on the headlights and I have a question. Once I connected the new harness to the headlight junction boxes, things were a little squirrely. I traced one problem to a bad dimmer switch. I replaced that and everything worked but one headlight on low beam. I checked the bulb and that was fine. I looked into the bulb socket and discovered one of the contacts was missing! The "thumb tack" had been pulled out of the wire at some time. It was in the can but that is a moot point as the new harness will have soldered connections. Anyhow, what I am really after is, does anyone know which wire on the original harness powers which headlight beam? Besides the black parking light wire, there is a red wire and a blue wire. I can not find a color scheme on any of my wiring diagrams. I could probably take the battery out of the car and run a few tests to figure this out myself but it would be much easier and quicker if someone can tell me which wire is which. Another thing is, a friend was helping when we disconnected everything and he neglected to note the color arrangement at the junction block when he disconnected them. I know the order the wires get connected to the junction box but does that order start at the front of the car. That is, the order is parking, low beam, high beam. Does the parking light wire go closer to the radiator or from the other end? I know electrically it doesn't make any difference as long as I maintain continuity throughout the harness but I would like to keep the hook up as it originally was. I now take numerous photos so hopefully this kind of thing won't happen again. Thanks. Beamer

My wire on the high beam indicator light on the speedometer is the same wire color as the high beam headlight. there should be two wires on the high beam switch. you might look there. just a suggestion.

I can't help with the color but both sides would be the same. The color and position of the wires on the working side should be the same on the non working side.

Beamer

I'm facing a similar problem with my 41 Coupe, so I invented my own solution. For whatever it may be worth, here it is.

Based on the forum of your post, I'm assuming you are wiring somewhere in 1937-42. It is my understanding that original wiring for those years was not coded by solid colors; rather, different patterns & colors of tracers were employed. So when not using original-style wiring, we need to improvise some other system that makes sense.

According to Wm. Crouse's Automotive Electrical Equipment, (McGraw Hill 1942) pp. 471-472, a widely-followed convention uses Black with Red tracer for headlight high-beam and Green for headlight low-beam.

Considering the foregoing convention, it seems logical that your Red would go to high-beam and your Blue to low-beam. At least, it seems more logical than the reverse.

As for sequence or position of wires on junction blocks, perhaps you could rely on shop manual wiring diagram for your car, even though it is unlikely that it was drawn for that purpose. Using 1941 car as example, the order (from front to rear on left side and from top to bottom on right) could be parking, headlight low, headlight high, and horn. Unfortunately, orientation of junction blocks in the 1941 wiring diagram is not clear, so interpretations can differ. (Note: 1941 shop manual has mis-labled diagrams, reversing truck & car.)

Guy

41guy, Yes, the main wiring harness did use different color tracings on a neutral color wire. However, the headlight extensions did use solid colors. I believe you are right that the red is to high beam and the blue is to low beam. With regards to the junction blocks shown on the wiring diagrams, they are oriented sideways so those are no help other than showing the relationship of the three wires to each other. Beamer