A/C shuts down in stop & go traffic, Why?

[Wayne67vert]

I'm pulling a 29 ft 5th wheel and my a/c is shutting down at low speeds and under acceleration from stop lights. It cool great once up to hightway speeds. I had the freon checked and the guages read with good numbers. While idling the high side goes up to 450 and then the fan turns on and the numbers fall back to the 250 range. The air from the center vents is 39 degrees.
What controls how the fan is activated? Would my running a superchip programmer affect this?
Any and all help is appreciated.
Wayne

[Wayne67vert]

I drove yesterday without the programmer and still had the same problems. No a/c in stop and go traffic. I'm headded for Texas and will get it into a repair facility there.

[gtnit]

well if you said it only kicks back on when i hit the gas i would say a shim needs to be pulled out to bring clutch in closer but scince it seems to be temperature related and is fine cruising speed then i wouldnt know what to tell sorry.

[Wayne67vert]

Had it repaired today....bad fan clutch, and recharge the a/c.