I am a DIY wanabe. So far most projects have been successful with more time than is supposed to be needed, but it takes a while to figure it all out, ya know! recent install of euro lamps a grat success!! thanks board!

My car: 1992 400e, 168,000 miles...real good shape.

OK, my issue is my right rear side marker. It is not working, but all other lights are. The bulb is good (swapped with L side). From the diagram I have, the ground is shared with other RR lights, so it must be OK. the fuse is shared with LOTS of other items that work fine. I removed the RR cluster and the wire from the connector to the bulb is fine.

any suggestions?
Where is the failure relay box that would be the next step up stream from the connector?
Is it rare for just one wire to go dead like this?
Please share any info you feel may help. I did search, but found mostly 'bulb out indicator' problems...which I do have 'on' my dash.
thanks!
John

Hi. I had the exact same problem with my old '90 300E. It turned out to be a faulty / worn out light check control unit which is located with the other relays behind the fuse box. It basically looks like a big multi-relay. Replace that with a used one if you can that works. I am not sure how much a new one is.

The problem is most likely something wrong at the individual bulb socket. Often the springy metal will get corroded or lose its spring. Take a good close look at the socket itself, clean the contact with something (electrical cleaner, steel wool,etc.) and try to bend it "up" a bit.

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Steve
'93 400E

I would second the suggestion to look at/clean the bulb socket, and then I would replace the bulb with a new one.

I had this problem with my '87 300E, same bulb socket. It would not work unless the light cluster was jarred (whacked, really) from the outside. I cleaned the contacts and replaced the (working) bulb with a new one, and the problem has not come back since.