When I first got the car (last Nov) the glow plug light would flash after I started the car. I replaced all the plugs and the problem was solved. My new problem is that (1) The glow plug light will come on (and stay on) after about 5-10 min of driving. (2) The glow plug light also will stay on (for as long as I have the key to the #2 position) while I am getting ready to start the car. If I turn the key off and then back to #2 position, the light will sometimes work correctly (stay on for 10 sec or so) or will be "stuck" in the glow mode until either I decide to start the engine or try to get the light to work correctly by going over the start procedure again.

Once the car has started....the light stays off and will then come on (and stay on) after I have already been driving for 5-10 min. What do you guys think is causing this? Relay???? Also, will I "cook" the glow plugs if the light stays on too long while I am driving. This just started a couple of days ago.

The car:

1980 240D with pencil type plugs

thanks,
mike

Looks like we have the same car, a 1980 240D. My glowplug dash light has never worked properly. I don't think you will cook the glow plugs, my guess is a short in the light. My seat belt light will often come regardless of the the status of the seat belt.

Good luck. If you find the culprit, please let me know. I'm chasing down the glow plug issue -- as well as a few others -- myself.

When the GP dash light comes on and stays on, I would check the GP with a voltmeter or test light to see if they are really energized. I suspect they are not because if they are on continuously, the battery will go dead because they draw more current than the alernator can supply.

P E H

I fixed the problem with a new glowplug relay. It was not cheap....but fixed the problem.

This is a bit late as the problem has already been solved, but I'll post anyway. I had this same situation on my 82 300D T and found that the "O" ring around the glow plug relay case had deteriorated and let water in the case. I opened the case, poured the water out and dried everything off and all has been fine since. Perhaps this may help someone else.