Exterior light warning light on dash goes off and on
 

The car is a 124 300D. The warning light for a burnt out exterior light bulb comes on from time to time and stays on. All exterior lights are functioning and light as they are supposed to. What gives?

Any thoughts appreciated - Ron

You either missed one (license plate bulbs???) or you have a bulb that is on it's way out, or a corroded socket/bulb end.

Hi Ron, the license plate bulbs are often overlooked, but if they're o.k. check all the taillight bulbs for discoloration. I've seen many discolored bulbs that light up, but still cause the warning indicator to light. Good luck

in addition to the advice already posted on this issue,there is also the fact that if the incorrect type of bulb is fitted-i.e. wrong wattage-then although the exterior light such as a number plate or brake light will work but the warning light bulb will still come on.This is often overlooked!.

Something that's often not mentioned is the way the system operates. The 'bulb out' warning will come on only after the bulb in question is energized. This means that if your left turn signal light is out, for example, the bulb out light won't light until the first time you use your left turn signal light.

Use this logic to help you track down the errant bulb.

...and ignition circuit bulbs (brake lights, indicators, reversing lights) cause the warning to stay on until the ignition is switched off whereas bulbs switched by the main lighting switch (head, side, tail, number plate) allow the warning to go out as soon as they are switched off.

Don't forget tail bulbs are 10W instead of the usual 5W.

Thank you to all of for your replies. Good ideas - never thought of.

Ron