I have a 2001 Chevy Venture, this fall all of the sudden the air conditioner quit blowing cool air you can push the switch for AC but it doesn't light up or blow cool air. and the rear defroster quit working,you can push that switch but nothing lights up or works.

Is the ac compressor clutch and pulley turning ?

The fact that its blowing cold on one side means that the AC system is working correctly . However the air flow is controled by vacuum actuators inside the the dash board . There controled by engine vacuum and open and close little dors inside the duct work that roots the air into the cabin . Unfortinatly there not always that easy to get to with out removeing the the dash .Look up under the dask try to follow the duck work it may be just stuck or a disconnected hose or a split hose But your AC system is working and this is where the problem is . Good luck with it

hi
you need to check the switch
it must be replaced

oh yes, a fuse (or two), plus a relay. jumper the pigtail to the low pressure switch on the low pressure supply line near where you would add freon. if the ac comes on and blows cold, there's is such an electrical problem, maybe even that switch. but if it comes on and only blows cool or hot you're low of freon and the system is keeping itself off to protect itself. again maybe that low pressure switch.

2004 chevy Avalanches air conditioner blows hot air, can the actuator be forced to keep it blowing cold air instead of hot air all the time.

possibl ac compressor clutch problem,cooling fan at rad not working so ac goes into high press mode and turns off(so it doesn,t blow system apart,built in safety)not enough r134 in system(low charge)

check the vacume / or the vacume regulator for the door exchange from hot to cold there might be a vacume problem.

here somtin---http://www.modifiedlife.com/2001-chevrolet-venture-car-stereo-wiring-schematic/----see if this will help

Try recharging the AC unit.

I had this problem. Chevy dealer repair shop found a collapse air duct.