Air Condtioner gets hot when idleing.....HELP!!!!

My friend has a 99' cavi and when he sits at a red light his car temp heats up and the air condtioner gets warm......but when he takes off and doesn't have to stop for a while the thing gets ARCTIC COLD.........what could it be? when he turns his ac off the engine temp cools down ......and it sounds like the compresssor is contantly coming on and off......any info would greatly appreiciated........BTW this is my first post and the forum looks good so far!!!!!

My guess is that the electric fan for the radiator is not coming on when the A/C turned on. Possibly the fan is bad or the sensor (s). It should automatically come on when the A/C is turned on to draw air through the unit and thermostatically when the engine reaches a pre-determined temperature. He should get it checked soon before he causes himself a major headache.

i had the same problem a couple of years ago, for me it was the cooling fan was shot, take it to a shop and have them check the sensors and
fan itself.

Usually if a comp is cycling very often it is under charged! Have the system checked for proper charge. The comp turns slower at idle and does not pump enough gas to keep cool while driving the extra airflow and speed of the comp makes it colder.