W140 / 1992 500SEL Instrument Panel Malfunction

Hi all, Ive developed a serious electrical malfunction in my instrument panel. All the lights are going crazy and all the guages are dead. Otherwise the car is operating as normal. the dealer recommeds changeing the cluster, but I would like to see if its not some relay somewhere? I checked all the fuses, all are OK.

I have a link to my website which has a 1Mb clip displaying the problem :

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Anyone know what may be the culpret, or how to remove the cluster?

Thanks! Jim

Reply to
jimbobeleeeeeoooooooooooeo
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I think it is a possibility that you just have a ground problem... pull the cluster out and loosen the grounds where all those brown wires attaches to the body metal... examine... make sure there is positive bare metal contact (not over paint)... and retighten.

Reply to
Tiger

Thanks for the info Tiger! I will check it out tomorrow when im not so tired, and let you know. I spent the whole night getting that damn cluster out. Turns out it just needed a little shove from behind. Now I gotta screw back all the things I took out trying to clear space!

Anyhow, I took the cluster apart, the circuit board seems fine, there are no obvious burn marks or charred bits. So brown wire should indicate ground, ,Ill check that out. Barring that ill need to find out what each pin on the 4 connectors are expecting and try reproducing the light show on the bench.

Jim

Reply to
jimbobeleeeeeoooooooooooeo

On Thu, 26 Aug 2004 02:49:15 GMT, jimbobeleeeeeoooooooooooeo

Tiger, I inspected all the browns, and yes all solid browns go to ground. They seem visually solid, and resistance seems correct. I am left with the possibility of a power source issue.

When I rig up power and ground to the cluster on the bench, ,the lights are all solid, so Im gonna go with a power problem. Unfortunately I have no pinout or spec or cd to get more info. anybody have a pinout handy? I did some searching on MB other forums and there was a guy with a simiular problem to mine. He also had his car sitting for a while, and when he tried firing it up-dead cluster. Another user gave this recommendation :

"Hi, check the fuse in the top of the overvoltage protection relay, located in the firewall at the base of the windshield, it could have blown during the jump. Sounds like a bad (i.e. corroded) ground, though. Check the fuses in the fuse box: some of mine were corroded on the ends where they make contact and acted as if they were blown. I will research and pass anything else along."

Anybody know where this fuse is on the fusebox? I dont read german!

Anything helps! Jim

Reply to
jimbobeleeeeeoooooooooooeo

Actually it looked to me like some sort of computer failure mode display?

Perhaps your instrument panel is fine, but is trying to tell you something?

Can you check the code status of the vehicle?

Marty

Reply to
Martin Joseph

I would then change the fuse for the instrument cluster... german is not so far from english in some words... and you can also use babelfish to translate.

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Reply to
Tiger

Hi guys, thanks for the support thus far. Sorry been busy at work and furiously trying to debug this bastard. I think I have finally hit on the suspect. A faulty voltage regulator on the circuit board. Im going to the local electronics store tomorrow to verify my findings and test out a solution.

I have tested the fuse, it seems OK. Also I found out if you flip the german side over, there is English!

Also, the grounds seem solid against the chassis, and no other malfuntion is present. I was able to reproduce the problem on the bench.

Lastly, the dealer wants $1500 for a new cluster + P&L&Tax. Wouldnt it be funny if a $2,000 job turns out to be equivilant to a $0.50 component? Local parts supplier wants $600 for a used piece or a "refurbished" piece. After talking to the dealer and finding out this is not an uncommon failure for the W140, im starting to think VCR repairmen are on to this....

Follow the money, as they say....

Ill let you know my findings...

Reply to
jimbobeleeeeeoooooooooooeo

Hmmm,

I am also an electronics tech... Keep us posted.

Marty

Reply to
Martin Joseph

"jimbobeleeeeeoooooooooooeo" wrote

Actually the moral of the story is that if you can't afford to maintain these expensive and complex cars you shouldn't own one.

h
Reply to
Harvey Louzon

Actually I think Jims point is that the electronics in his car are an embarrassing bunch of crap.

Can you afford to pay for an embarssing bunch of crap? You can? Oh.

My take on this has always been to buy the older vehicles with less complex electrical accessories. I like manual systems where possible (seats etc.) as they give me less thing to break.

I have over the years troubleshot many problematic systems including Fiat fuel injection and lovely lucas (Lucas last words? Don't drive at night) in all flavors of British cars and many classic american cars.

It's surprising that the VDO instrumentation setup in such a high end vehicle would be such a complete hack design wise, but maybe it was just a bad year?

Then again, although I could "afford" a newer car, I am notoriously cheap. Still Jims car sure does look like a sweet ride...

Marty

Reply to
Martin Joseph

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