Here's how I fixed mine. Uninstall the lamp (I think it's 3 or 4 bolts). Get some sandpaper and scuff the offending part of the "printed circuit" portion of the fixture (not really printed circuit, but looks like it). This is usually where the prongs of the bulb holder make contact. Scuff it up really good with sandpaper, then get out your soldering gun and flow some solder into the resulting pit. Problem will be solved.

To avoid recurrence, get the proper bulb from the dealer. Most of these problems are caused by using an incorrect bulb, which can heat up more than spec and cause the housing to warp. The warping causes poor contact, which leads to arcing, which leads to pitting.

Unfortunately, I soldered mine back in January and it just returned a week or two ago, so this fix appears to be needed every year. No problem, I can spare 10 minutes with a soldering iron rather than breaking out $$$ for a new tail lamp.

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08 W251 R350
97 W210 E320
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85 W126 380SE Cranberry
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