86 300e side marker lights
 

I read some threads re the bulb fault indicator. Mine is on also. I believe it is the rear window brake light and the right rear side marker. I tried non dealer bulb in the side marker and it won't light. I then took the left bulb and installed it on the right and it stiill won't work. I then ran a volt test and I get 4.6 volts on the right rear and 8 volts on the left. What gives?

Check grounds (brown wire)

I've had trouble with the right side rear marker light too. Its design is very problematic, the way the bulb is perched in it's clip. Make sure there is good contact.

I later purchased a used bulb housing....and then had the same problem with it. :confused:

I've had problems with the RR side marker light as well. In my case, a new bulb solved the problem. Even though the old one worked occasionally, the contacts must have been partially oxidized or something.