How to test a glow plug controller?

[Full Monte]

My '88 F250 won't start and I'm about to dig into it. I presume the glow plugs are shot, but don't want to put in new ones if the controller is shot, too. How do I test it? The dash light turns on when I turn the key. The batteries crank it real well. It will start after a lot of cranking. It puts out a lot of white smoke after a long cranking session. Thanks!

 

[HammerDown]

there is a step by step procedure located in the Haynes Diesel manual if you can locate one. That and a 12volt test light and a multimeter is all that needed.
I'm pretty sure those steps are located somewhere on this forum too > if someone could direct you to them

 

[J D Recovery]

connect test light to pos battery and touch the glow plug connecter if it does not light its bad.that is the controller. Now the gps With a meter set to ohms look around 2 ohms. I removed them and put battery voltage to each one for 5 seconds and checked with a noncontact thermometer should read above 500 degrs

 

[Agnem]

Check you glow plug controller relay by placing a volt meter across the heavy lugs. If you have at least one good glow plug connected, you should get battery voltage when the relay is not activiated, and zero volts when it is (meter set to 1.0 resolution)