So who can help me figure out where the sensor is that runs my gauge, I've hear its a single wire on the back corner of the head, but I can't find any wires or sensors on it that could be it. I've found a large plug in the head that I've heard is where its supposed to be, any info is helpful I need to figure this out asap.

Better buy a Cummins Tstat or you'll be replacing it again.

I'm not concerned with the thermostat at the moment i got the failsafe one so at least it'll fail shut if it fails. that doesn't answer key question about where the other sensor is.

Well truck finally threw a code tonight. P0118. Ect voltage high input. Basically the wiring is jacked going into the plug and needs fixed. not to worried at the moment since I'm wiring my glow shift setup tomorrow.

ok so got the glowshift gauge hooked up and the temperature is still fluctuating, except tonight on my way home from work it hovered just under 200, then dropped to 180 and stayed at 185 for the rest of my drive ( 40 minute drive, did it around 25 minutes in). can you guys think of anything, i've bled the system 3 times. im starting to think either my water pump is about to shit the bed, or i have a blockage somewhere. I have no loss of power, no white smoke, and the coolant has never gone over 200 on my gauge. any help is appreciated, im really not wanting to do the HG but i will if i have to.