Hello! I'm new to this forum and a quick search didn't turn up an answer to my problem. I drive a 1988 240 GL with 256K miles and I recently had new tail lights installed as well as the circuit lamp boards. The tail lights were operating fine for a few weeks but now when the lights are on (headlamps or parking lamps) only my third brake light comes on. Neither the right nor the left get brighter when the brake pedal is depressed. I checked the bulbs and they seem to be fine although the circuit boards seem to have a bit of play in them, that is, they don't sit perfectly on the tail lamp assemblies.

I know tail lights are a frustrating issue and I don't possess much skill at self repairs, but can someone offer some recommendations. Is this fuse related or more serious?