Does anyone have a good readable color version of the wiring schematics from a color service manual from 1964. My current investigative work involves trying to figure out why both tail lights come on with the light switch, and why only the drivers side brake light works. Meaning the passenger side lights only currently just are on but do nothing when breaking. However if I mess with the fixtures in the housing the lights sometimes will go off depending. Hope this makes sense.

 

I’ll tell you what, if you had a simple test light (like I suggested in your other thread), you could make this far easier since you’re now doing the wire(s) wiggle test(s). Just hook (clamp) black to ground and start probing along each wire(s) length with the pointed probe.

 

Chances are that its a bad bulb or light socket connection. You probably don't need a colored wiring diagram to figure this out, left brake/directional lights yellow with a yellow jumper wire to the other lamp, right brake/directional dark green with a green-white jumper to the other lamp and tail lights are a black wire. Just a test light or meter.

 

Those style sockets are notorious for this problem. Replacements are no better.

Disconnect battery, then use an L-shaped pick or other hook to gently pry the two contact strips outward and re-establish tension on them. You may also find the grounding sleeves have worked their way slightly out of the plastic socket bodies which also makes the bulb contacts lose contact with the contact strips. You can try pushing them back in but likely to be a temporary fix.

Poor design, plain and simple. Yet GM stuck with it for years.

 

Since the tail lights work, I doubt its a ground issue. I agree with the internal socket tab issues.

 

x2

 

Sorry I’ve been sidetracked, what is actually happening is the passenger break lights come fully on when I turn on the headlights. When I push the break the drivers side lights up to match the passenger. When pushing the breaks (no lights on) only drivers side lights up. I even changed to mew sockets and made sure to pull those tabs and such. When comparing to the wiring diagram, there’s enough wires but they’re not easily identifiable. I’m not seeing a yellow one or a
light green one. Just a red and black and a green and black

 

Look to see if the red wire is spliced in somewhere in the trunk harness. I'm assuming its on the drivers side. Make sure the bulbs are in correctly on the passenger side as some of the offbrand imports you can install them 180* out. They should all be double filament bulbs.

 

^^x2^^