on my '91 the warning lamp that tells you that you have a burned out light keeps going on and off for no reason. i have checked all of my exterior lights both when the warning light was on and when it was off (even fog and reverse) and also had my mechanic check for burned out lights and it still turns on and off, also my left turn signal flashes at about twice the speed it normally should, but not always, only sometimes.

its very annoying to have one of my warning lights on and i cant figure it out. im guessing theres a short somewhere in the lighting system, but where?

also, i only have one rear fog light, on the drivers side, theres no place to put a second one. i think this is the way its supposed to be, but want to be sure.

thanks

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1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

Grdenko,

My indicator bulb would go on and off occassionally. Finally tracked it down to one of the two bulbs that illuminate the license plate. I had to check it out in the dark and when the indicator light was on.

Chuck

I doubt it is a short in the wiring. Perhaps a bad ground since your signal is flashing fast. Perhaps the sensor that detects that a lamp out is bad. Good luck.

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2004 Toyota Sequoia Limited 4wd
1991 Lincoln Town Car Executive
1991 Cadillac Sedan DeVille
1988 Mercedes 300SEL
1972 Chevrolet Caprice Kingswood Estate 9-passenger wagon
1973 Pontiac Grand Ville
(Prior MB's: 1974 240D, 1985 380SE, 1984 190D, 1993 400SEL)

Liscense plate lamp is a good possibility, and so is a lamp you replaced (or the PO replaced) and didn't replace the other lamp of the pair at the same time. I don't know how sensitive the MB is to exact lamp current, but the Volvo will give fits if the lamps are exactly the same, and even then some brands will give an intermittant lamp out signal.

Check the condition of the lamps that flash too fast -- could be some corrosion at the bulb socket, or mis-matched bulbs (one brand new, the other nearly worn out).

The senor compares the current draw for the two lamps and will turn the light on if they differ very much. Volvo uses a set of magnetic switches, I don't know how MB does it.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

1. Single rear foglamp is correct

2. Bulb failure module is very sensitive. The behaviour of the warning lamp helps find where the problem is;

If it is an ignition switched circuit giving the problem (brake lights, reversing lights, indicators) then the lamp comes on when you first try to use that light and stays on until the ignition is switched off.

If it is a circuit controlled by the main lighting switch (side/tail lights, number plate, headlights) then the lamp comes on when you switch on the faulty circuit and goes out when you switch it off again.

Check all the bulbs are the correct wattage (tail lights are 10W not the more usual 5W) and there is no corrosion in the bulb holders.

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Mick J
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)