Testing Glow Plug Controller M998

[MIBOAT]

Hello Folks,

I have a glow plug controller 12338772 (2920-01-175-7214) that I'm trying to test for resistance between the pins as descried in the AM General manual and the military books. However, I get no resistance readings whatsoever. I figured I had a bad GPC until I received two new (old Stock) ones that finally arrived- I'm also getting no resistance readings with these. I have not tried installing the new GPCs

I've tried a Fluke multimeter, another digital multimeter, and a simple analog meter... all showing nothing between pins the manual specifies.

Any idea why I'm not getting readings? Of course all three could be bad, but that would be just terrible odds...

I've poured through a ton of posts on here [thank you ALL!] regarding the PCB, GPCs, Glowplugs, etc. Just trying to eliminate culprits before I shell out the big bucks for newest PCB system.

 

[AAVP7]

Those instructions in the TM are just for "non-solid-state" GPCs. It says so somewhere pretty well hidden in the TM. "Non-solid-state" GPCs are the really old ones. They used a series of relays to create the switching logic.
They seem to have been replaced by now in most vehicles by solid-state ones, or by solid state temperature senders. And there seems to be no testing procedure for these.

 

[MIBOAT]

Am I correct this is the older relay style?

If so, I’m getting no resistance readings where I should. Maybe I shouldn’t be, but I’m surprised that my two NOS ones are also testing bad.

 

[86humv]

12338772 NSN 2920-01-175-7214 is only used with PCB 12446779 or CR2692.
What PCB or EESS box do you have?