I was getting an ! warning light everytime I turned on the lights with a "Tail Light" warning on the console. I had checked all the lights and they were all working. I had read that the 928 was sensitive to light bulb types and corrosion so I decided to clean all the sockets and replace the bulbs.
There are 8 bulbs (6 12v x 21 watt and 2 12v x 10 watt) in the tail light and 1 in the side marker (12v x 5 watt) on each side. The total cost was about $12 from DEVEK. The tail light lense is held on by 4 phillips screws. There were 4 rubber washers on the inside of the lens that also needed replacing. I found corrosion on 3 of the bulbs/sockets and one bulb where the glass part of bulb turned separately from the base. I sprayed all the sockets with electrical contact cleaner and replaced all the bulbs.
The side markers are held on by 2 wingnuts on the back side of the fender. I removed them, the washers and a small bracket, then pushed the marker light out the side. I cleaned the socket and replaced the light, then reassembled. I attached the rear bracket, washer, and wingnut before pushing the marker light back into the fender. This made it a lot easier then triing to put them on once the marker was in place because of the limited space.
The whole process took about an hour. I hear the third brake light (center) is also on the circut, but my car doesn't have one.
Copyright 1999, George A Suennen