I’ve been working my way through trying to figure out why I have issues with reverse lamps, trunk brake lights and the constant 12v to stereo and the computer. I’m not great at reading the schematics, but I have tried to see if there could be a common cause. The reverse switch is working (I took the slope off). Tested the lights on the trunk (all working). I ended up realizing there is a trailer harness and if I jump off that everything works. I’ve tested all the fuses and swapped any relay that could possibly be related (to my knowledge) Anyone got an idea of where I could look next? I cleaned up all the grounds in the back behind the rear light fixtures as well. The trailer harness works perfectly, so in theory I could just use that for the trunk brake light and reverse lights. All the other brake lights are working. I’m guessing those two issues are connected, but the constant 12v is also a problem, likely separate. If I let the car sit for a a day or two both clocks reset. (Computer and aftermarket stereo)

 

The radio should have 2 live wires, 1 is constant live for the radio memory and the other is switched with the ignition.

 

This makes no sense, but I believe I found the issue for the reverse light. If I bridge the brown and green wire the back up bulbs come on. So I then tested the switch directly off the battery using a test light. The switch seems to perform just fine. But then if I hook the switch up to the leads and depress the ball I get nothing. The only thing I can come up with is directly coming off the battery gives enough power to make the switch work correctly. I’ve never encountered anything like that, but I’ve ruled everything else out. I ordered a new switch, so I’ll know for sure, but it has caused me some mental issues because until I removed it and tried it off the battery it appeared to be working correctly.