Hi,

The bulb warning light is coming on without reason. How does the system work is there a control unit that's gone faulty, all the conections at the lights look ok and it's got no aftermarket lights fitted.

Thanks for reading

I.E. "License Plate" lamps?
good bulbs , But metallic contact rail in Rear light(s) doesn't contact the Bulb(s)
contacts.
Good Bulb,But wrong wattage.

you want Osram (European Sylvania) bulbs of the correct wattage.

FREE,FREE,FREE Mercedes Electronic Parts Catalog:
http://epc.startekinfo.com/epc/subscribe.jsp
(So , you can look up your own parts.)

Service manual:
http://w124-zone.com/downloads/MB%20CD/W124/Main.html

ETM:
http://w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/ETM.pdf

Oh,yeah it's called the "Exterior Lamp Failure Monitoring Unit" (A.K.A. "N7")

__________________
'84 300SD sold
124.128

Thanks for the reply, I'll check all the bulbs are the correct type as well, and have a look at the metalic strips to the rear lights. If it still plays up I'll swap the unit now I know where it is.