At first colder day, my glow plugs don't make a light until after the car is running. Haven't check it out yet, it is still starting fine. But I can tell it is not optimum on prestart GP.

I maintain 4 80-90s MB, and this symptom is the first. Here is what I know:
-battery perfect
-glow plugs good
-no loose GP wires
-Fuse good

I suspect ground.

Any ideas?

Wayne