65 GMC headlight wiring harness

[aphaynes]

Originally Posted by weeniewawa

you can do a search for relays and wiring for your situation but here is a diagram, there are lots more out there, this one is not labeled as good as others but you get the idea

I decided to implement this wiring scheme this weekend. After getting it all done, the sun was down so good time to test it. One high beam was not coming on while the other was nice and bright and one low beam was dimmer than the other. At first I was thinking "what did I wire wrong?" , but then I assumed it couldn't be the relay wiring or, in the case of the high beams, neither would work right. So, I was thinking grounding or something. Yes, I already had some issues prior to implementing the relays, so I figured while implementing this scheme I could figure out what the issues were.

So, the next day, when I had sunlight again, I started removing the headlight bezels. As I pulled them off and one of the lo beams flopped out, dangling by it's connector wires, I realized the 49 year old plastic adjusters were all pretty shot; either completely broke or cracked pretty good on all the lights.

Ok, back to wiring. Got my meter out to start trouble shooting, turned on the lights, and when I grabbed the dangling lo beam light that was dim and moved it, it suddenly brightened up. As I moved it around it fluctuated from dim to bright. I figured, the contacts in the connector must just be dirty....and they were. However, cleaning them did not solve the issue. As I held the connector and squeezed it, the light brightness would again fluctuate from dim to bright. I assume the connector is just stretched/sprung/worn out from being so old. I repeated the process for all of the lights to find the same results. Even the Hi beam that was off came right on when squeezing it's connector. So, relay wiring good...all connectors worn out. Once I replace them, all should be nice and bright again.