When I first got my 300D, four months ago.. Nothing electrical worked. It started, and ran. But that's about it.

-No brake lights
L Headlights
L Wipers
L Radio
L Cruise
L Int. lights
L Fuel gauge
L alternator would not charge
L Would not start without jumping the starter block under the hood (faulty neutral switch)

I was able to solve MOST of those problems (mainly by cleaning contacts and jumping my neutral safety switch!) All but a few other oddities.

The glowplug light does not function during a glow cycle. The light is good, I know this as it "brightens" when the engine approaches 3,000RPM

High beams work, but when they're switched on the dash gauges go dead and my glowplug light comes on.

Tach jumps to max when the horn is blown.

Cruise does not work, (suspecting the amp) but the cruise servo "twitches" as the engine is running. Making a rather loud clicking sound. I would really like to fix the cruise system.

Power windows function intermittently -- Clay fuses are to blame, I''ve cleaned and scrubbed the contacts. Replaced the old clay fuses with new ones (copper - not aluminum elements) and coated them with dielectric grease to deter corrosion. Still I find myself rolling my fuses in the pannel to get my windows to work. Sometimes in the rain!


Alright guys, tell me what you know!

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Vehicles:
2002 SLK 230
Gone but not forgotten:
1983 300D
1981 El Camino 'OILBRNR' - 6.2L diesel
OM617 powered '86 F150
1984 BMW 524td
2001 VW Beetle TDI
1994 Sunurban 4x4 6.5L diesel

I didn't have the same set of gremlins, but replacing the electrical part of my ignition switch removed all the electrical gremlins I had.
I wish it were that simple for vacuum gremlins!

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

I don't know much about electrial problems, but I had the gauge cluster out of my 83 300D today and when I was putting it back in, I accidentally plugged the large round multi pin connector upside down. All kinds of odd things were happening. Turn signal indicators were the bottom lights, the fuel gauge was jumping around, etc.

Do you think it is possible that someone had your gauge cluster out and installed the round multi pin connector wrong? Most of these plugs can only fit one way, but not so with this particular plug. It is located behind the fuel and temp gauges, down low in the back. You can push the cluster out a bit from the back. Just a thought.

Good Luck. KRW

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1991 350SDL 350k+ miles

Also check all the electrical grounding points.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

With the speedo cluster removed, you will see many brown ground wires connected to a common bolt. Remove the bolt, clean all ground wires and reinstall the cluster making sure the guide pin on the multiwire connector is correctly plugged in. Be aware that the oil gauge is mechanical, so be gentle in removing the oil line at the back of the cluster, use 2 wrenches! DO NOT start car with cluster removed. You will shoot oil all over the front seat!! Window fuse contacts could be pitted or have weak tension on the fuse ends.

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.