86 Diesel Golf , glow plug light stays on .

Found out what the problem was. need to drain water out of fuel.

I haven't come across that problem on my '84 Rabbit. But I would assume that it is an electical problem only. Make sure your grounds are OK and that you don't have a short somewhere. Also, get your hands on one of those electrical testers where the bulb lights up if there is current. With the car good and cold, have somebody turn the key to the first position. In those first few seconds, put the tester on each glow plug and make sure you have current. Then, once the glow plug light goes out but stays dimly lit, check for current again. If you don't have current this time, then you know that the plugs are turning off and that your problem is simply the glow plug light staying lit.

-Bryan