HELP !!!! Gauges, all of them, are not working

[rickjordan]

I posted this problem on the tech forum, but I thought I would post it here as well. Yesterday the car was fine, but when I went to come home from work, I had no fuel level, water temp, speedometer, oil pressure, RPMs, or turn signals. The clock works as well as the "economy" guage, that's it. Even though the turn signals don't work, the hazards do. All interior and exterior lights are working. I looked at the fuses and they appear fine.
I need help quick. Is this whole cluster electronic and maybe a connector in back came loose? For my '83 TD, the oil pressure is a direct feed form the engine and the speedometer is mechanical.
Any insights would be greatly appreciated

[Otto w. Coers]

Same thing happend to me two days ago. The fuses look fine, but I had to twist/turn them in their holder to make contact. Works fine now!
Good luck!

[rickjordan]

So you are saying that on these SLs the speedometer and oil pressure are electronic. I'll definetly give it a shot.

[tecqboy]

Everything in the instrument cluster is entirely electronic: no speedo cable or oil pressure line. If the fuses are good, possible cause may be a bad ignition switch. Try just wiggling the key a bit. Consider upgrading to the newer brass fuses if you don't already have them. They sell a "kit". The cluster can be sent out for repair. Do a search on this forum.

[rickjordan]

The fuses are the old aluminum ones and quite a few have corrosion on them. I have tried turning all of few of them but a few were stubborn and didn't want to turn. Boy could MB find a worse place to put a fuse block? What doesn't help here is that the label saying which fuse does what, is missing. According to the owner's manual it is supposed to be attached to the cover. I will use a pair of needle nose pliers and turn the fuses that were gicing me trouble. Hopefully this will "break" things up and get some power going again. If there is one fuse that runs the entire cluster, why then would my clock and economy gauge still be working, when everything else is dead?
This "kit" is this from a dealer, if so how much roughly?

[tecqboy]

You can probably get the fuse kit from Phil at fastlane, the guys who support this forum. If not there, then **************.com for sure. The price is quite cheap. I believe that the clock and mpg gauge are powered from seperate supplies. I don't have a wiring diagram of the cluster. I've had mine out to replace lamps, but never any other problems. You need a set of special "tools" to "pop" it out. It's not difficult. Search this forum for the procedure. The cluster is actually a complex module of electronics. It may have a fuse of it's own, but I don't recall seeing one. Often in electonics of this nature, a special very fast CPU fuse is used to protect the processor. Fuses do wear out. In 40 years of electronic experience, I've seen it happen many times. Vibration and heat fatigue cause the failure, not an over current. Hopefully someone here can post a pix of the fuse chart.

[Otto w. Coers]

The clock can not be on the same circuit as the gauges because it would stop working whenever you turn off the vehicle. The clock should have power at all times(unless you disconnect the battery). The "ecconony gauge" is probably nothig more than a vaccum gauge connected to a manifold vaccum port and therefore does not require any electricty to operate. If you find and corrosion on any of the fuses you should take them all out and clean the contacts properly. I would doubt that you have to replace the whole fuse-box.

[ctaylor738]

I'll end the suspense. The guages are on fuse 5 - 8 amp. You can get a nice little fuse kit with a puller at just about any auto parts store.

[tecqboy]

FTR The economy guage is NOT a vacuum guage, at least not in my 129. It is an electronic meter movement display. It is driven by a circuit which compares the true vehicle speed with fuel being used. A vacuum guage would have a reading at idle even with the vehicle standing still.

[rickjordan]

Well, the problem is fixed. I did this before reading the last couple of posts.. I remembered that I had a fuse kit in each glovebox of the 2 diesels. I went and replaced the fuses that looked bad, even though they weren't broken. Now everything works as it should.
Thank you very the tips.