I have a 82 240D which I’m restoring. To remedy the 3 watt dim dash lights I’m replacing these with LED’s lights to increase illumination. Plus to enhance the general appearance. After replacing the bulbs on the left and right hand side with the cluster un-mounted from the dash and with enough room to get your fingers in and around the light socket, I carefully removed the old bulbs and inserted the T-10 Wedge led’s and reconnected them into the cluster. As I turned on the dash light, I experienced a small puff of smoke coming from the back side of the cluster as well as the normal electrical burn smell. This I figured was not a good thing!


I sensed that I either drew to much current out of the circuit and/or burned out a component or blew the rheostat. After this little episode, I started to check out other things like, fuses, and did the car still start. After determining that all systems still seemed to work, I noticed that the lights on the center console where my manual climate control / fan speed and the horizontal section where the shifter is, the lights for the door switches no longer illuminated. I’ve read on other forums where the light rheostat does not control these lights, but the fact remains that when I smoked what ever component that was in the dash, it affected the other lights also.

I strongly believe that it’s the rheostat that was cooked. I know this can be bypassed on the 300d’s for I have one from ebay I bought to learn on and to sample another repair which needs to be done to a broken odometer. I’m using this to test prior to committing to the real car.

I don’t have a problem with buying a pricey new dimmer switch, but for testing purposes, can the rheostat on the 240D be bypassed ? Also, if other MB enthusiasts have replaced those dim w123 dash lights with led’s, what type where used?


Thanks in advance for any help.
Greg