My friend just bought a 89 X-cab longbed K3500 6.2 when he turns the key the glowplug light doesnt come on. He hears them go on then off, but it wont start, it turns but to ignition. He replaced the gp controller. Should he replace the relay? Also, where is the relay? He says it is on the drivers side behind the intake manifold, but on my 84 it is on the fender, where is it?

 

Anyone?!

 

If he can hear them go on and off, then the relay must be good. Sounds like all the glow plugs are dead.

 

Maybe the fuse is gone, I was driving one day and she just quit..tried cranking it over..not a kick.. I noticed that the wait to start light wasn't coming on.. a fuse under the hood was gone.

 

the glowplug light could be burned out. also check if electricity is going to the glowpluugs

 

Isnt the relay and controller on the same module?? YOu can check the resistance of your gp's somehow to see if they are good or not. I cant remember how to do it.... Search on the internet, you will find it... did the light ever come on to begin with?