bulb failure indicator
 

I changed the blown bulb 12v10w for the back light but the bulb failure indicator is still on.
I cleaned all terminals and all bulbs are correct ones.the indicator light should only come on when I turn the lights on but mine stays on all the time!
Any suggestions?
Thanx
91 300E24V W124

I'm new to Mercedes, but my Volvo also has a light that indicates a burned out bulb. Apparently these indicators compare the resistance of each bulb in the circuit and then illuminate if the resistance is found different. The solution (usually) is to replace the burned out bulb with one of the same manufacture as the corresponding "good" bulb. Though this dosen't always work. Clean terminals are important as this can cause the resistance to vary.
Mark

I had the same problem with my 1988 300E, I checked all the lights, the high and low beam, fog lights, all 3 rear brake lights,license plate lights etc. All looked good but still that darn indicator lamp stayed lit. I ended up replacing perfectly good bulbs with new bulbs and the light went out. Is the light indicator coming on as soon as you start it or when you turn the lights on or step on the brake, that will give you an indication of where to start. When I stepped on the brake, the indicator light lit up. Seems a lot of people miss the license plate bulbs but again...most probably the top rear brake light (third brake)

I have always changed the lamps in pairs: if one brake light is gone, I change both.

This ensures that the resistance of the bulbs is the same and indicator light is off.

If you change only one bulb of the main lights, the other one will be gone in some weeks anyway.

I had the same problem before but now the problem is gone. The indicator is so sensitive that a slight change in output would trigger the switch. WHat I did is to turn on all the exterior lights then stand far from the car to check the brightness of each bulb. I discovered that one taillight was slightly dimmer than the others. I replaced the bulb but tat the same time, cleaned all the terminals and more importantly, I made sure that the contacts were all ok. You may need a long nose pliers or srcew driver to bend the contacts a bit. I also used sand paper to "scratch" the contacts.

Hope this helps

This is a good thread about light bulbs and MB lights overall, including fogs: MB Light bulbs

Haasman

very often this one is overlooked...

a lot of good thoughts here.


firewalker: where are you in dayton and what kind of benz do you have?

peter