Can someone tell me (1) where and (2) what color is/are the wire(s) that control the illumination of the stuff in the center console on a 124. I'm talking about illumination of the shift lever position (PRND2), the window switches, speaker fader, pwr. mirror control, HVAC controls, and the row of switches above the HVAC controls (emergency flasher, rear headrest and light control, antenna, etc.). I assume there is one or more wires that run from the headlight switch to somewhere in the center console that tells that stuff to light up when you turn on the headlights. Everything in the center console works as it should (so I know it isn't the fuses) except it has no illumination, and no way all the bulbs burned out simultaneously. Thanks

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car

There are GY\BU wires and coming from instrument illumination rhostat switch power is from headlamp switch (hot all time) to fuse box #3 fuse and exterior lamp failure monitoring unit.also has n40 instrument illumination control unit is a relay if I recall relay is locate behind instrument cluster with four wires also check your fuse #9 is power to the relay.

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MB STARS Master Guild Technician,17 years MB tech
14 years independent shop owner

MB Stars, thanks for your reply. Does "GY/BU" mean a grey wire with blue stripes??? Do you mean that wire runs between the dash light rheostat and the headlight switch? I actually removed the rheostat (which wasn't working right) and jumpered the 2 points where it connects. It sounds like you are saying there's a wire that connects to the rheostat (I don't remember any being connected to the rheostat, but I guess it could be under the circuit board) that runs to the instrument illumination relay (I didn't realize there was such a relay). Thanks again for your help.

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car

Illumination control relay is right behiend instrument cluster next to warning module almost same size of the warning module
Illumination control relay has four wires #1 is red coming from fuse #9 power #2 gery\red to connector x6/1 behind ashtray #3 is ground #4 grey\blue from instrument cluster rheostat switch (instrument circuit board)

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MB STARS Master Guild Technician,17 years MB tech
14 years independent shop owner

MB Stars, thanks again. I found the relay. I determined I could get the center illumination to work by jumping the #1 and #2 sockets on the connector. That tells me the problem the connection behind the ashtray is good. I suspect the problem is that #4 has a bad connection at the instrument cluster or the relay itself is bad. I guess I should check #4 for continuity. Thanks for your help.

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car