Myles Maycher

My right rear tail light very intermittently will stay on and kill my battery. It has been anting because if I do not catch it my battery will die and it happens so rarely that I sometimes forget to check. I’ve looked at the wiring diagram and it looks like the driver and passenger side are powered through different circuits. It has been challenging to test because it happens so rarely. I have been able to confirm. When the passenger rear tail light is on with the car off and headlight switch off there is power at the fuse box. I tested it with the fuse out. To me that means it most likely is a faulty switch. Also sometimes when the problem happens and I switch the lights on and off the problem goes away. Sometimes it does not. I just have not been able to test the switch when it’s not working.

is there something I am possibly overlooking. I am going to order a new switch unless someone thinks I should look at something else.

Hatzenbach

only a workaround: but how about you replace you taillights with LED taillights? They draw way less power.

John McM

Sounds like the headlight switch. On my car the rear light and small light in the headlight are on the same circuit. As you said, each side is separate.

Metal Guru

Sounds to me like a wiring harness issue; chafed wire going to ground or touching an always hot wire.
It might be time to physically inspect the loom.