APU Coolant Temp Overheating?

My APU condenser fan is not turning on at all. Temp goes over 170 F and APU turns off a few seconds later. I am using a laser temp gun to check the temp on a bolt next to the thermostat. I also bought a new fan, but I still have the problem. What can be causing this problem? APU alarm code is ENG on a Thermo King APU Tripac (2013 model).

 

I checked all my fuses, and they’re all working. I’m guessing it’s a problem with a wire or some sensor if there is one for something like this.

 

I remember asking Road Rescue department at a mega fleet about leaving the valves on or off, and they said it didn’t matter. I’m referring to the two valves under the hood (located on the passenger side on my truck). I must admit I did close them off recently, and that’s when the problem started.

 

Oil level is good. No oil leaks. I check under my APU daily.