Tested my glow plugs today, because after reading a bit on GP's failing, voltage goes up on the others, eventually burning up most of them or all of them, and then the controller. Well after testing each one, i was only pulling 10v. batteries are charged, truck still fires, but it wont cold start unless i hold the manual GP switch on for a min. of 9-10 seconds, then it fires up right quick. So i'm thinking it could be a dying GP controller. Any input fellas?