Hi all, I am in the midst of fixing my '89 Volvo 240 sedan. While fixing the brake lights I noticed on one side (the passenger side)the dual filament bulb stays full-on bright as if the brake pedal was pressed whereas the driverside brakelight is fine. If I move the socket just right the light will dim to normal running brightness however when the brake pedal is pressed the light goes out all together. I am using the proper socket, a 3 pronged white socket and the proper dual filament bulb so i am confused as to what is wrong. If there are any other volvo people out there who could help me out id appreciate it very much. Thank you very much.
-N
I’m not saying you don’t know how to insert a bulb properly, but, it is easy to insert it backwards. Doing this will guarantee a brake light effect.
Barring that, there may be a short in the wiring somewhere along the way from the switch to the rear bulb socket. Perhaps fraying from rubbing on metal.
Also, bad grounding can cause this. My '88 Toyota has a ground wire that attaches to the bulb housing at the hold-down bolt. The light housing is plastic, so they needed to use a ground wire. But, the screw came loose, and the bulb lost ground. It back-feed the brake lights through the tail-light circuit looking for ground. Check to see if you have the same problem.