[ChevyGuy]

Definitely check the coolant level, but the description makes me think it's a bad fan.

But first: Make sure it's really overheating. It's possible with the A/C off the computer will allow the car to warm up a little more before kicking in the fan. My old car would sit rock steady at 1/2 if the A/C was on, but if it was off it would go up to 3/4 before the fan would kick in and cool it back down to 1/2. I haven't turned off the A/C in my Cruze long enough to see what it does.

 

[ChevyGuy]

A/C off due to high temp sounds like T Stat. What year are you? if 11-12 you can see the digital temps.

Except it cools off when he gets moving again.

I'd check to make sure the fan spins freely and nothing is jamming it. Otherwise it needs to get checked out. Looking at my service manual (2013), it's a 3-speed fan. The control system has 5 relays (KR20C, KR20D, KR20E, K20F, KR20P) and 3 fuses (F42, F45, F46). Given the complexity, it must have been designed by a intern as it seems needlessly complex.

 

[ChevyGuy]

I'm not sure how the fan works internally, but given all the different relays, fuses, and 3-speed, it seems like it should be running at some speed. I think I'd inspect wiring to make sure something hasn't popped out, or has shorted out.

Personally, I'd troubleshoot it rather than throw parts at it and hope I'm right.

 

[ChevyGuy]

OK, there's a problem. I'm not sure what to suggest other than checking fuses under the hood. The circuit is complex enough that you'd need a wiring diagram and a test light to trace anything.