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Discussion Starter #1
1992 400E, 229K miles. While engine is running all my instrument gauge needles sit at zero and ABS and ASR lights are both on. Also, there is a buzzing that sounds like the door buzzer but very muted. Cruise also doesn't work, which was working before.

Happened after I came out from the store and started the car.

Neither of the two engine harnesses have been replaced but there is no exposed wiring either.

I'm guessing its a problem with ground.

Car runs just fine. But I might be doing 100+ mph, on fumes, at 8000 rpms, and boiling over and ready to explode...and without the "idiot lights" who would ever know?!

Any suggestions?
 

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1992 400E, 229K miles. While engine is running all my instrument gauge needles sit at zero and ABS and ASR lights are both on. Also, there is a buzzing that sounds like the door buzzer but very muted. Cruise also doesn't work, which was working before.

Happened after I came out from the store and started the car.

Neither of the two engine harnesses have been replaced but there is no exposed wiring either.

I'm guessing its a problem with ground.

Car runs just fine. But I might be doing 100+ mph, on fumes, at 8000 rpms, and boiling over and ready to explode...and without the "idiot lights" who would ever know?!

Any suggestions?
Have you checked the fuse and replaced with copper one (if not already copper) ?
Ground for instruments generally supplied through main instrument plug towards left side of cluster - big circular plug. See if you can pull cluster slightly out (lots of posts on this - not hard at all) and check everything at back plugged in okay.
 

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Discussion Starter #3
Thanks for the reply. Yes, I've checked all aluminum fuses which all look fine but do plan to change to copper once I find them for sale. Also on my to pull the cluster. Thanks for the helpful suggestions.
 

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Thanks for the reply. Yes, I've checked all aluminum fuses which all look fine but do plan to change to copper once I find them for sale. Also on my to pull the cluster. Thanks for the helpful suggestions.
Mercedes Ceramic Fuse Set NEW GERMAN 8-16-25 amp set | eBay

Can't ask for cheaper than this for a full copper fuse replacement set !

And macdrone is right there is a fuse on the cluster. From memory it is just to the left of the speedometer about middle circuit board.
Looks like all the other light type twist lock bulb sockets but has a fuse strip inside.
 

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Discussion Starter #7
Thanks everyone for your feedback. So far today have searched the factory wiring diagrams, checked fuses, as well as fuses on ECU, and explored areas I've not been to before. Number 6 fuse powers the buzzing noise I mentioned and removing it stops all blinkers which I'd like to have, just because. Would have pulled cluster next but honey-do's demanded action, so tomorrow I'll pull that and the console to recheck the aftermarket radio I installed a few months ago since there's also no sound, although there is power to the headunit. I'll check the new amp for power. Antenna works. Only area I've been messing with lately is the oil pan and oil pump suction to clear the screen of chain guide pieces. To get there I disturbed the knock sensor wiring, but I insulated that from the oil pan to ensure there wasn't a short, and that I rechecked and I am convinced its good. Also scouted the routing of the lower starter to alternator harness, which hasn't been disturbed, and it seems good enough to not be contributing. Will also look at the voltage regulator tomorrow, which is probably original, to swap the new one I've been planning to install for months but have held off to decide my solution for the lower harness which may give up the ghost when I move wiring athe alternator. The M119 vs M104 & M103 voltage regulators are totally different projects, mine being much more involved than simply removing the back cover. Anyway, sorry for the long post.

If anyone sees a common cause for these seemingly unrelated symptoms, please chime in. And for all who have already offered up ebay fuses, and other ideas, thanks much.
 

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Probably a good idea to check the voltage regulator. See what kind of volts you have on the battery:

Check voltage Key Off Engine Off, KOEO and Key Off Engine Running KOER.
KOEO >11.4Volts
KOER >13.2 but not higher than 14.2volts

That ground you were talking about isn't a bad idea to check either: W1 Main ground (behind instrument cluster) Behind left side of instrument cluster 235-5

Go ahead and replace the fuses 5,6,7,9 and 16.
 

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Discussion Starter #9
Well. How about that! The last bloody fuse fell apart as soon as I yanked it. Replaced them all this morning and yes it was, as many suggested, and old, decrepit fuse: #5. And yes the clues were there all along....tach, instrument, radio...

Moral of the story: start with the simple stuff; measure twice, cut once; use your eyes; don't panic; step back from the brink.

Another lesson learned, hopefully.

Thanks all. :surrender: :bowdown: :eek:

Now I'll check the voltage regulator. Anyway.
 
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