Fan stuck ON

[Autonomy_Lost]

Okay so I think its fixed. I replaces the fan switch with a REM one, and now the fan kicks on at the middle of the green arc, and kicks off at 185 degrees which is the bottom of the green arc. Does this sound correct?

 

[Milcommoguy]

Sound's to me you REM edied the problem.

Real parts for real HumV's, CAMO

 

[Mogman]

Jumping in here because I'm having an issue too now. But its weird.

The other day my fan failed to come on, and my temps kept climbing. I unplugged the TDM module which made the fan come on. Then, as a troubleshooting step, I plugged the TDM back in, and unplugged the temp switch (the one by the thermostat housing). That also made the fan kick on, leading me to believe the temperature switch is bad.

So I replaced the temp switch with a new one, and at first I thought the problem was fixed because the fan kicked on at the exact right time, but then never turned off. What the heck!

The system is "failsafe" so with the switch open or the wire disconnected the fan runs, it shuts off when the switch closes or you short the two leads together.