Instrument panel lighting help - PeachParts Mercedes-Benz Forum

psaboic · #1 09-03-2018, 11:33 PM

Ok, I need a little assistance with the instrument panel lights. My problem is that they do not work! Ok they worked fine (except needing to jiggle the rheostat knob occasionally) before I took out the instrument panel to fix the clock. Now, they simply do not work. (Clock works fine though ). At first I thought it was the rheostat, so I jumpered it by soldering a wire between the brass contacts on the back. I measured it with a meter and I got 0 ohms between the contacts so I figured it would be good, but still no lights. I checked the fuses and they are all good. The climate control lights and shifter light do not work either.
So, unless all the bulbs decided to go out at the same time, I have a wiring issue. For starters, can someone tell me which of the several connectors on the back of the panel carry the voltage for the lights? Is it the single 12V wire that plugs in behind the tach, or it is the multi pin round connector that plugs in on the left side of the panel? If it is the multi pin, can you tell me which pin.

Many thanks,

Glenn

optimusprime · #2 09-04-2018, 08:59 AM

PSA you will need to remove the clocks again to repair the rehostat just remove it from the back of the console i think 3 or 4 screws ,.Then you need to open it up .Mine had fell to bits inside . Or if it is worn out you can join the joints on the top of the switch so the lights are on full all the time but you will have no dim operation

psaboic · #3 09-04-2018, 09:35 AM

I already jumpered the rheostat so the lights would be on full all the time, but still no lights. I will pull apart the rheostat to see what it looks like, but I still think it is a power problem, therefore I need to know which pin (or pins) on the 15 pin round connector the power for the lights comes in on.

Diseasel300 · #4 09-04-2018, 10:54 AM

You could potentially have a poor ground. The instrument cluster uses a common ground that's made where the various pods screw together. There should be a metal strip under there that can become oxidized and make poor contact. It may not be the problem, but it's worth a look.

psaboic · #5 09-04-2018, 06:52 PM

Worth a shot for sure. Still would like to trace the power though.

psaboic · #6 09-05-2018, 12:18 AM

Ok, if no one has the answer to which pin on the 15 pin connector carries the 12V for the instrument panel and console lights, can someone point me to a wiring diagram that I can use to trace out the circuit?

Thank you,

Glenn

dieselbenz1 · #7 09-05-2018, 07:13 AM

Try this link. http://www.peachparts.com/shopforum/diesel-discussion/346954-instrument-cluster-repair-2.html

psaboic · #8 09-05-2018, 09:48 AM

Dieselbenz1, you are my hero! Seriously thank you very much, this is exactly what I need to get started. Greatly appreciated.

Glenn

psaboic · #9 09-08-2018, 08:08 PM

All Fixed. New replacement tach works great, and soldering 2 broken traces on the printed circuit board fixed the no instrument light issue. Thanks to all for the help and assistance.