While the tail lights are out of the way I can do a little rust mitigation. I cleaned up inside the rear corners then I masked off the holes and sprayed rust converter inside wherever I could. But it was hard to get all the nooks and crannies. I gave it a day to cure then painted with rust encapsulating paint.
I modified a disposable brush by breaking off most of the handle to let me get the back of the rear panel. When I actually did the painting I wore gloves. And a good thing too. I used the brush where I could then a spray can to try and get the rest.
While the paint dried I started tracing the brake light circuit. Almost immediately I found a problem. The brake light switch is bad. It has 30 ohms resistance all the time. At least these are fairly cheap.
I traced the circuit back this far this the connector at the bottom of the steering column. There is some creative wiring down here. If the wiring is not the problem the turn signal switch probably is. I need to find a better diagram so I can trace back through that.
I also checked the horn button. The horn is getting power but the horn switch does not ground the wire. Once again I might have to dive into the steering column.
When this car left the factory it has a crap electrical system. No fuse block, lots of circuits with no inline fuses, and high-current devices like the horn and the headlights go right though the dash switches. There should be a relay on both. The horn would be really easy to mount a relay. And as I look at it I think I could use the headlight junction block here to put the headlights on a relay too. Instead of powering the headlights directly the headlight wire would close the relay and connect a direct line from the battery to the headlights. The parking lights would still be going directly off the battery but that is a lot less current. But this is a project for later.
Meanwhile I unmasked the tail light holes and pulled out the wires. This should be fairly simple. with 4 wires coming down for the tail, backup, and turn signal/brake lights and one white wire for the fuel gauge sender. Then three more wires go across to the other tail light and one wire should go out to the bumper for the license plate light. Instead we have wire nuts, cut wires, loose wires for God knows what. I will have sort out each of these. Here you can see I have a test lead on the top yellow wire. I am using the meter to verify this is the supply wire for one of the brake light/turn signals. But why are there two wires going out to the bumper?
This is a terrible picture for two reasons. First it is a bad photo. But also it shows a crazy knot of splices, wires twisted together and taped, and one exposed bullet connector. How this car never burned up is beyond me. This will all have to be sorted. But the paint is wet and smelly so I decided to do something easier first.
Sunday I masked off the tail light buckets and painted them with silver spray paint. For a smooth, run free finish I dusted on lots of light coats. It turned out nice. Notice how bent the one stud is. I am tempted to try and straighten that but it came out that way and if I break these castings I am in a world of hurt so I will let this sleeping dog lie. Once the paint was dry I pulled off the masking. Looks pretty nice.
I tested both buckets to make sure the light sockets were good. The first one worked perfectly and I took this picture with the lenses sitting on top. I like it. Then I burned my finger on a hot bulb like a dumbass.
The second bucket did not go so well. The brake/tail light bulb was loose in the socket. The only thing providing tension against the bulb is this rubber plug that fits in the bottom of the socket. The rubber is a bit soft and mushy and the contacts are pretty worn. So now I have a problem.
This was plan “A”. I found an o-ring and put it in the grove on the rubber plug. It did not work. But it is still a promising idea and I will try some other size o-rings. Plan “B” is a standard contact pigtail. That might work but it will be hard to keep it from rotating in the socket. Plan “C” is to replace the whole socket but that will be a tricky thing. But this is enough for one night.
Putting the o-ring UNDER the rubber bit worked. Ship it.