I too have a 2003 TC33D with glow plug light problem. Mine comes on like it should and when its time to go off it sometimes stays on and clicks like every second trying to shut off but stays on. One day it was on for a good 30 minutes and clicked like every second or 2. Its random now when it happens. Sometimes it works and sometimes it dont. It always stays on long enought start, but i have problem getting light to go out. i have tried wiggling switch while it is on to try to get it to go out but it didnt help. If i have time someday I will find that relay(timer) and clean connections.
mike
mike