HELP! -- Electrical Problem -- Instruments on Dash Kaput!
 

I've got a '95 E320 and this afternoon I turned the car on and noticed that all the alert lights stayed lit long after they normally were supposed to be lit. So I turned the car off, turned it back on, and everything was fine. It's a hot day so I put the airconditioning on.

About 10 minutes later, while I was driving along at about 10 miles an hour, all of the needles and dials on the dash board went dead, as if the car'd been turned off --- everything except the speedometer. And at the same time, an obnoxious electrical buzzing sound that I've never heard before --- like something was shorting somewhere in the far left side of the dashboard --- started and kept going.

I noticed that if I turn my left or right signal blinker on, or, turn the hazard blinkers on, the buzzing immediaately stopped (but the dials on the instrument panel of the dash stay dead). And then if I turn off the blinker, the buzzing immediately resumes.

When I got home I checked the fuses and they all seem fine. I turned the ignition on without turning the car on, while I had the hood up, and the loud buzzing sound is coming from the far back of the fuse box, behind the fuses. I can feel the whole metal enclosure vibrating when I touch it.

Anyone know what this is all about?????

Is this going to cost a lot of money to fix???

(Car has 134k miles by the way)

My 1990 did this once. Even though the fuses looked fine, there was one that was bad. I just happened to brush against the bad one and everything started working. It was just barely broken in the center. You might check again.

My 1990 500SL had much the same symptoms and one new dash cluster later my problems are gone- except for that large visa bill I have comming later this month.

Thanks brewtoo. I went and checked again, and re-seated the #5 and #6 fuses and problems went away. I think at least the #5 fuse had become slightly dislodged. The fuse itself seems to be intact, but I'm not sure there was a good connection. All problems have gone away now.

Please keep us updated. I had the same exact problem to my 95 E320. The buzzing is from the turn signal relay box (i had it replaced at the tune of $140. All my fuses looked good, i messed around with the relays and what do you know, the car worked!! For a little while, then it went out again.

I have a young friend who works for a Mercedes dealership. He thought it was the ignition switch. It wasn't. The park neutral switch. It wasn't.

He finally found a wire in the dash that was broken. He is going to fix just that wire and see how it works.

Hope yours is fixed for good with the fuse. Let us know.

Jimmy

For problems like these first I would spend $3 and change ALL the fuses. Use the old ones for emergency. Then check the ground on the dash. In my case a new ground wire soldiered to the back of the instrument cluster fixed everything.

Good luck.

Beware of deceptive fuses!
 

I know this is an old thread but thanks guys for saving me who know how much money! I can now cancel my dealership appointment and keep my money.

After reading you post I went and completly pulled fuse #5 out. The conductor crumbled in my hand. I had tested this same fuse with a multimeter earlier today and it tested OK.

My 95 E320 had the symptoms described above. No start, no guages worked, buzzing from the combo relay (Turn signal, rear window defrost, Int. wiper relay). I took the cover off the combo relay and the center, turn signal relay, was going crazy! That explained the buzzing. I am going out tomorrow to buy replacement fuses and junk the 11 yr. old ones.

Thanks again!

Isn't this one of the models with the dreadful wiring harness? Perhaps it is deteriorating and causing those items to be on the fritz? Just a thought.

Fuses!
 

Yes it is. However, that is for the engine wiring harness that is exposed to heat, water, etc. I replaced mine about 8 months ago. That is a completly seperate issue. The #5 fuse's conductor had just oxadized over time and become very brittle. This caused a very small fracture in the conductor that was not visable and also apparently "connected" when I tested it with a multimeter. I did replace my old fuses and hopefully they will last 11 years like the old ones.

my 94 s600 instruments went dead out of the blue. dash lights work, temp guage works but the speedometer, odometer, oil pressure, gas guage and tach don't. Will re check fuses as per above. Where is the ground to the instument cluster located?