interior lights problem - please help w124 300d - PeachParts Mercedes-Benz Forum

#1 11-13-2002, 02:44 PM

Hello,

Last night went to the gas station, filled upand when I turned my headlights on, everything worked allright except interior night illumination such as the dash cluster, all switches lights, power seats lights, light switch illumination. The radio, cigarette lighter all work OK, the warning lights within the cluster all light up when the ignition is turned on, turn signals, horn, inside light that turns on when the door is opened, buzzer, evertyhing. I checked all the fuses, every one of them is good and tested outside the fuse box, then put back in. Still no little lights.
What do I do ? Anyone knows what to check ?

Thanks

Marius
1987 300D w124

JPL · #2 11-13-2002, 02:55 PM

Just a guess, but it could be a flakey illumination rheostat (dimmer) that is usually part of the odometer reset knob near your fuel guage. Try turning that slowly to see if the interior instrument lights flicker and get brighter and/or dimmer.

Just a hunch. Maybe give it a try.

#3 11-13-2002, 08:13 PM

This same thing happened to me and I traced everything on that circuit.
Here is what I found out. The fuse ends had a little bit of corrosion on them, I pulled the fuse and buffed the fuse ends and fuse clips with some emery cloth. I reinstalled the fuse and it worked. Here is a list of the items on that circuit. Check and see if any of these other items works. If they do them most likely it is the rheostat (common).
Right front and rear, parking lamps.
Heater illumination lamps.
Instrument cluster illumination.

Good Luck!
Robert

190D22 · #4 11-13-2002, 09:32 PM

Both of them offer great tips there. The reason why your switches lost light along with the cluster illumination is because there are 'fiber optic' (I put that in quotes because I don't know if they are truly fiber optic) lines that go from the cluster illumination sockets to your switches. When my tach side bulb was burnt out my rear defroster, sunroof, and antenna switches did not light up. Now that I've replaced that bulb they all have light now.

Since it's both bulbs that went out (this is correct?) at the same time it's either the potentiometer dimmer, the fuse, or a ground wire somewhere.

Good luck with getting the lights working again!

If you're interested in updating your cluster illumination... check this site out. http://www.superbrightleds.com/cgi-bin/store/commerce.cgi They sell HID LEDs that are designed specifically for auto illumination. They have built-in resistors to be able to operate with the car's 12V and they fit in the cluster's sockets.

#5 11-14-2002, 08:56 AM

Thank you all.
It was a dirty dimmer switch. I pulled the cluster and cleaned the inside of the rheostat. It all works great now.

190D22 · #6 11-14-2002, 03:21 PM

Sorry that link I sent doesn't work. Here's their main page... http://www.superbrightleds.com/led_prods.htm

In the LED car lights section they have the bulbs I was talking about. I'm going to get myself some white ones.