Thanks for all the replies - some clarification:
I was not clear enough in the initial posting.
The car does not have the hardtop on at this time so no dome lights to check. I don't recall any on the hardtop anyway, and since it's stored away elsewhere, can't run out to check it.
Yes, it's got the factory front fog lights but even though they work fine, the bulb itself is missing so unable to check to see if it comes on with the fog lights are on. However, knowing that this is the function of the green light, it's a small matter, since I was thinking it would help warn me when I leave the lights on in the car.
Come to think of it though, once I replace the bulb, and I drove with foglights on(to make myself more visible since the main headlamps are so weak)then I would see the green light still on when/if I left the lights on after shutting down the engine.
Not sure the door switch is the problem, the warning module does buzz at me when I open the door and the keys are still in the ignition...does that not signify proper operation? Or could the warning module still have partly malfunctioned and not give a warning when the lights are on and the engine is off?
Is there an aftermarket warning device I can hook up to my '75 450SL that will give a warning if I leave the lights on?
thanks for all the feedback so far.
Network Integration Engineer
MCSE, CLP, CCNA