VW Golf Strange Tail Light Issue?
Okay, so here is the deal. I have a 2008 mkV GTI that I have owned since it was new. I have had this problem going on for a while now, and I have not been able to solve it.
My left tail light function completely normal. The running lights, blinker, and brake lights all work as they should. However, my right tail light is where the issue starts. Each tail light has two hemispheres to it, both of which go on a dim setting for the running lights, and both which go on bright for brake lights, but only the outer hemisphere blinks for the blinker (two bulbs, same negative terminal). Upon first impression, it will seem that everything is working normal. If I hit the brakes, both the hemispheres light up properly. If I turn on the running lights, then both hemispheres also light up. However, if I leave the lights on for anywhere from 10-40 seconds, or I turn the right blinker on, after a few blinks and or that time, the outer light goes out. I have tried new bulbs in the tail light, switching bulbs, and cleaning connectors. I also do NOT get a bulb out warning when it goes out, however if I unplug the assembly, I do get the bulb out warning. I did think it was maybe a heat issue, so I got out a later thermometer and measured the bases of the inner bulb (which has no issues) and the outer bulb (the one with the problem), and before the outside one went off, the base on the inner bulb would be around 180 deg F, while the base of the other bulb would be around 110 deg F. I don't know if this temperature difference signifies anything, but it might be related.
Is there a board I can look for that might have missed that controls light function? I don't think it's a fuse, because then the light should be out the whole time. The light will come back on when I brake again if the running lights are OFF, but if they are on, I have to turn running lights off then on to get that bulb to briefly come back on. The front blinker also does not flash quicker when that rear bulb is out (so I think the circuit is still complete). I can get a voltmeter to check that the bulb is receiving the correct voltage, but I think it still is. One thing to note, when the bulb goes out, I can hear a high pitched humming noise coming from it.
I tried to do research on this topic, but there seems to be nobody else who has posted an issue like this. I have found other things where the turn signal or outer bulb will go off instantly when brakes are pressed or hazards are turned on, but mine seems to have a delay, like something is building up and tripping.
Any help with this problem would be appreciated. I want to avoid the dealer on this one before they try to replace 100 parts.