W124 lighting gremlins

[Deleted member 11979]

Hello everyone,
I have just bought a 94 w124 e220 and have a couple of questions.

The "blown bulb" orange light illuminates on the dash when you turn the lights on. All of the exterior bulbs are working fine, however, I have noticed that the light on the fan switch does not illuminate, also the lights on the lighting switches (roatary switch to the right of the steering wheel, headlamp levelling etc) don't illuminate. Could this be the cause of the blown bulb warning light, or do I need to dig deeper? I notice also that the rheostat for the dashboard lights doesn't allow you to dim them, they seem to be stuck on full, it almost feels as if the knob is not connected to anything as it roates too freely.

The second question is regarding the OTG. Sometimes it seems to be pretty accurate, others it rises slowly to over 50 degrees C, other times it is blank, anyone know where to start looking first to cure this one?

Thank you very much in anticipation

 

[SilverSaloon]

not sure, but double check both the rear number plate lights, as these trigger the bulb, also the side-lights

 

[Deleted member 11979]

Seems to be all fine is that department, thanks anyway.

 

[w124coupe]

I always suggest new 124 owners swap all the fuses (about £3 from halfords) as they corrode badly and cause all sorts of problems with resistance on various circuits - pop a few and see if yours are rotting!

 

[w124coupe]

The various dash bulbs are easy to replace - just make sure you get the right wattage replacements to avoid any melting of plastics!

Re the rheostat, you need to pop the cluster out and then you will be able to see what's going on.

 

[mattc]

Hello everyone,
I have just bought a 94 w124 e220 and have a couple of questions.

The "blown bulb" orange light illuminates on the dash when you turn the lights on. All of the exterior bulbs are working fine, however, I have noticed that the light on the fan switch does not illuminate, also the lights on the lighting switches (roatary switch to the right of the steering wheel, headlamp levelling etc) don't illuminate. Could this be the cause of the blown bulb warning light, or do I need to dig deeper? I notice also that the rheostat for the dashboard lights doesn't allow you to dim them, they seem to be stuck on full, it almost feels as if the knob is not connected to anything as it roates too freely.

The second question is regarding the OTG. Sometimes it seems to be pretty accurate, others it rises slowly to over 50 degrees C, other times it is blank, anyone know where to start looking first to cure this one?

Thank you very much in anticipation

Check that all the bulbs are of the correct wattage. sometimes people put the wrong bulb in and the system thinks a bulb is broken.

Is the sensor clean? could be worth checking the price of a new one.

 

[Deleted member 11979]

Thanks for that, I'll start checking / replacing as advised, where is the temperature sensor located?

Thanks again

 

[w124coupe]

Behind and below front numberplate.