The glow plug relay unit has a timer in it. On some models it has a temperature sensor (separate) that only lets the relay turn on below a certain temperature. To test the system, make an indicator light of your own. Connect a small light bulb to one end of a length of small gauge wire (speaker wire is good), and alligator clips to the other end. Connect one clip to ground and the other to the glow plug bus. Rout the wire through the front door and hang it where you can see it. This will let you know whether the glow plugs are getting current or not. If they aren't, the trouble is in the relay or wiring that connects it, or the temperature sensor (if any).
The relay is a black plastic box on the left shock tower. If the glow plugs don't get current, use the same test light setup to see if the relay gets current, etc.
|