Late last year, I posted a topic regarding the dash lights on my 250SL. The center cluster worked but none of the other dash lights. I replaced the bulbs and re-attached the ground wire on the tachometer, but no go. This spring I took the car to my SL guru, and he resolved the issue after much head scratching. He found that the u-shaped bracket for the tachometer; the keeper, was incorrect. Along the way somewhere, the correct keeper had been replaced with a duplicate of the one used for the speedo. The tach keeper has a small bump out and rubber insulation (at about the 2 o'clock position when looking at the front of the tach). When I put the speedo keeper on it, replaced the ground wire, I had a short to ground that fried some wiring in the center of the dash. No fires, thankfully, but no lights either. He finally found a replacement (used) and the full complement of lights is now working. And let me tell you, on the 250, with the translucent heater levers, it is a thing of beauty.
As part of the process he also found that the wires in the connector for the left side rear license plate light had been switched. It was grounding out when I attached it with the regular screws.
I figured that these would be good finds for the group to tuck away in there collective memories for things to be aware of.
Jonny B
1967 250SL Auto