91 300e no dash lights - PeachParts Mercedes-Benz Forum

JordaanDMC-12 · #1 11-09-2009, 11:28 AM

Hey all,

well we purchased this 91 w124 and all seems well so far but there is no dash lights what so ever!! No center console lights and no a/c unit lights! I went to the fuses first and they all look fine.. Where do I even start? Lol

Rick Hall · #2 11-09-2009, 12:17 PM

You can start by turning the rheostat on the instrument cluster, the black knob sticking out of the speddometer face. This controls the brightness of the instrument lights. If you feel "roughness" when turning the knob, turn it back and forth vigorously to clean the contacts. If you get no response when turning this knob and your lights do not come back on, then it is time to replace the rhestat in the instrument cluster. Cost about $35-40.
Good luck

silversleeves · #3 11-09-2009, 04:03 PM

There is also a red fuse on the backside of the speedometer cluster. I cannot remember the part number but I had to replace mine and those dash lights came back on.

ps2cho · #4 11-09-2009, 07:10 PM

^ There are no fuses behind the cluster on a '91 model. Maybe that is for the later w124 models with the Electronic VDO.

Start by checking the bulbs and probe the contact. If there is no voltage follow a wiring diagram up to the fuse box and see if there is voltage at the fuse.

Caseyjones955 · #5 11-09-2009, 07:31 PM

The rheastat sometimes fails, it can be checked with an ohmmeter or by bypassing it. Also Im not sure if this applies to E class cars (mine is a 87 W126) but check the integrity of the circuit board adjacent to the rheastat, the etching tends to pop like a fuse, maybe this carries over to the E class as well. Something else noteworthy is these fuses can look perfectly in tact and be bad, you might just try replacing that fuse anyway.

silversleeves · #6 11-09-2009, 09:36 PM

Instrument cluster fuse #201-546-00-25
I installed this into the back of my speedometer (1991 300te) to get the dash lights to work again. It is red and it "twists" into the back of the speedo.
Really.

The little red one right in the pic.
http://www.peachparts.com/diy/w124inst_cluster/speedo_cable_disconnected.jpg

JordaanDMC-12 · #7 11-10-2009, 01:03 AM

Awesome, thanks everyone!!

I tried turing the rehostat and moving it all around but I got nothing. Nothing at all. I'm going to replace it and see if I have that fuse on my cluster and replace it also.

Can this cause all the lights not to work? And when I say all I mean the Dash light, A/C unit lights and center console lights? All the warning indicator lights work but not the actual nighttime ones.

JordaanDMC-12 · #8 11-10-2009, 01:07 AM

Quote:

Originally Posted by Caseyjones955

Something else noteworthy is these fuses can look perfectly in tact and be bad, you might just try replacing that fuse anyway.

That's funny you mention that, I had a great experience with that scenario on my 220D. The left headlight would not come on for anything. I checked the fuse and it looked fine so I assumed it was the light. Went to the junkyard got a new light and connector and plugged it in.. Still nothing so I spliced the connector with the new one and still nothing. Cleaned the fuse and port. Bam.. Came right on lol That sure was time wasted....

I will replace the fuse tomorrow. Probably clean the ports also with steel wool.

JordaanDMC-12 · #9 11-11-2009, 10:26 PM

FIXED!

It ended up being the rheostat, the copper line snapped off where it was soldered.. So my dad soldered it back and viola! Lights are now functional

thanks for the help everyone!