glow plug issue [Archive]

BasinD24

07-04-2009, 03:40 PM

Hi all, hoping for a little input since I'm new to diesels. I haven't looked hard at the system yet but I want to get a lead on where to look from y'all. For awhile my glowplug system has been erratic. The dash light would come on sometimes but not others. For the last few weeks the dash light has not come on at all. It's been fairly warm here so starting has not been a big issue, infact, I can't really tell if the plugs are working or not. Is this a temperature sensitive system? Would the ambient temperature (80* or so)be enough for the system to not operate? Or is this merely a timed system that would always come on when the key was first turned to the 'on' position? Also, is the dash light indicative of the systems operation? IOW, could the system be working and just not have a dash light?

TIA
Joel S.

heavyequipment

07-05-2009, 08:15 PM

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.

Slobodan

07-06-2009, 04:14 PM

My fix has been to make the glow plugs manual. Get a momentary push switch, and wire that to your relay and disconnect the automatic glow plug system. That way you have full control.

Jason

07-07-2009, 05:59 AM

It could very well be that the light in the dash is out, and the system is still working. Test it as listed above. If its starting ok, then its probably working. Even in warm weather, it will be a little hard to start with no glow plugs when the engine is cold, such as sitting over night.

Jason