1992 400E no dash lights - PeachParts Mercedes-Benz Forum

E93067 · #1 03-12-2004, 10:19 AM

The dash lights in my 1992 400E stopped working last night. No blown fuses? that I can tell? Where should start? is there a bulb somewhere that needs replacement? or is it more complex? some sort of glow element?

Thanks

E93067 · #2 03-12-2004, 10:29 PM

Ok, been reading up on this and it looks like I may have a bad rheostst. Anyone have any info on how to replace a rheostat? I'm guessing it involves removing the dash, and will probably require some special tool.

Thanks

hflederer · #3 03-13-2004, 11:37 AM

I recently had my orange digital readouts (immediately above and below the speedometer go dark. The temp numbers continue to show true, faint readings in daylite(LCDs I guess), but nothing shows in the digital speed box above the speedometer. No fuses blown, and my dimmer knob still works for the rest of the dash. No clue.

jrmd01 · #4 03-13-2004, 11:56 AM

A while back I was having problems with my electrical system. I checked my fuse and it looked fine. I was going crazy looking for the problem.

One day my dad's friend came over and while I was under the dash, he changed my fuses and asked me to check my problems...they were all gone. I looked at the fuse and sure enough the ends (where it contacts) were erroded. Simple 10cents fix that I overlooked.

Bottom line. Change the fuse first even if it "seems" O.K. If the old fuse is still good, use them as an emergency back up.

Sincerely,

jrmd01@yahoo.com

E93067 · #5 03-13-2004, 06:04 PM

Ok, just replaced all the fuses with brand new ones, but my dash still does not light up. Has anyone ever replaced a rheostat on this type of Mercedes 92 400E? Anything else I should look for? I already replaced the wiring harness when I had my valve job done a few months ago.

944s2c · #6 03-13-2004, 07:05 PM

Do your window switches on the console and the rear doors light up? your reostat also controls these. I had all my lights go out on my 300e about 7 years ago and fixed it by soldering the reostat. The instrument cluster must be removed to do this.Do a search ..Instrument cluster removal. Hope this helps, Dan

jrmd01 · #7 03-13-2004, 08:56 PM

1. O.K. fuse changed...
2. Now try checking/replacing the bulbs. (about $2ea)
3. If that doesn't work check the ground. (I ended up getting a ground wire soldered to the back of my instrument cluster)
4. Last thing that could be the problem is the Rheostat
5. If the lights still don't work, take it to the STEALERSHIP

When my car was having similar problems, I went as far as #3.

Good luck.

jrmd01@yahoo.com

E93067 · #8 03-14-2004, 02:12 AM

Yes, fuses replaced, I'm on to #2, the bulbs. How do I access them and where are they located?

I also noticed that none of the lights that are supposed to come on with the dash work, rear door lights, gear selector, etc...

If I get to #3, do I need to remove the dash hook up a ground wire?

I see #4 in my future....
Has anyone ever replaced a rehostat on a 400E? did it require any special tools? Are there any diagrams available?

Thanks to everyone for their much needed input, I'm sure I'll get this problem solved eventually.

jrmd01 · #9 03-14-2004, 10:49 AM

"I also noticed that none of the lights that are supposed to come on with the dash work, rear door lights, gear selector, etc... "

Looks like it maybe your rheostat or ground. You'll need to pull out your instrument cluster then replace your rheostat and solder a ground wire. Use the search function. There is a post that has pics and a step by step guide on removing the instrumnet cluster.

I have not personally replaced a rheostat, so I can't help you there. Sorry.

Good luck,

jrmd01@yahoo.com

J.HIDALGO · #10 03-14-2004, 11:03 AM

once you have the cluster out. You also may want to check the red fuse that it is behind the cluster. It looks like a light bulb but it is red. BTW, these instructions are for a 300e but, the 400e should be similar.
Another tip, while the cluster is out, change all your lightbulbs. They are not as bright as they get old.

spsinha · #11 03-14-2004, 11:18 AM

Check this link out, should give you idea at what you have to do. The problem is most likely your rheostat.
http://instrument.articles.mbz.org/renew/

400E · #12 03-14-2004, 03:22 PM

Quote:

Originally posted by E93067
The dash lights in my 1992 400E stopped working last night. No blown fuses? that I can tell? Where should start? is there a bulb somewhere that needs replacement? or is it more complex? some sort of glow element?

Thanks

Forgive me if this seems a dumb question, but I'm assuming you've made sure the rheostat (dimmer knob) isn't just turned all the way down? You wouldn't be the first (nor the last!) person to inadvertantly turn the rheostat down when cleaning the instrument panel, etc.

Even if that's not the problem, you might try just turning the rheostat back and forth a couple dozen times. This sometimes works, at least in the case of the radio fader control.

E93067 · #13 03-27-2004, 01:26 PM

Thanks again to everyone for all the helpful advice and suggestions that helpled me solve this problem.

It was the the rheostat that was causing the problem. Another very easy part to replace took less that 10 minutes to do the whole thing. The dealer wanted $200 to do this! I attached a pic of my failed rehostat.