PeachParts Mercedes-Benz Forum - View Single Post - '90 300 SEL: All instruments lights go out

Cal Learner · #4 04-13-2009, 08:23 PM

I don't think there's a lighting relay behind the cluster, it's under the hood together with the other fuses and relays. Sounds like what you're describing is the rheostat (potentiometer) that brightens and dims the interior gauge lights. If it's still the original pot and it's never had any TV tuner or similar electronic spray to clean it up, it's getting dirty and then it doesn't make good contact anymore. Result: dash and console lights flicker or are dim or disappear on you all at the same time. Not a difficult DIY, especially if you've already had the cluster out of the dash, and it's not big $ either.