A while ago my passenger side (right) main tail light bulb went out on my '95 944T so I bought a replacement bulb and installed it. It didn't help. I disconnected the wiring harness from the tail light assy and checked for voltage going to that particular light and found there was none. The tail light does, however, work on the driver's (left) side.

I find that odd since I had power on both sides and both tail lamps were working before. Why would I suddenly lose power to just one of the tail lamps ?

I started thinking that maybe there's something wrong with the bulb failure sensor since that appears to be where the tail light power circuit splits into two parts, one going to the right tail lamp and the other the left.

I pulled that bulb failure sensor and opened it up to take a look inside. The solder joints where the pins going to the tail lamps (pins 58R & L) attach to the main circuit board looked like they may be suspect so I reflowed them but it has not made any difference. Based on a visual inspection of the rest of the solder joints in the sensor using a magnifying glass, everything else looked ok with the unit. I guess that still doesn't totally eliminate the bulb failure sensor as a suspect but it sure leaves me to wonder if maybe I'm barking up the wrong tree.

Has anyone else ever had a similar problem with their tail lamps on their 940 ? If so, what turned out to be the source of the problem ? Other than a break in the wire between the bulb failure sensor and the tail lamp, is the failure sensor the only possible culprit here ? If not, where else should I look ?

I think I'll head out and do a continuity check from the bulb failure sensor to my right tail lamp to see if there's a break in the wire somewhere. I highly doubt that'll turn out to be the case...

Hmmm...I wonder if they used the same bulb sensor unit on the '89 744s. If so, I could pull the one from my partner's car and try it out in my 940 to see what happens...