A/C wont turn on

It turns on your a/c compressor which draws more power from the engine, in turn an increase in you idle spped

make sure that the climate control module is working properly and that the heater control is turning off os required

Yes , there is a relay . It is energized by the PCM - engine computer . When you push the A/C button on the climate control panel ,it sends a voltage input to the BCM or strait to the PCM .When the PCM see's this it will energize the relay ,if it see's the correct input from the high an low pressure switch .
The Trainer 40 When the compressor won compress

Roger it sounds like the blower motor is not comming on. There is a resistor network located in the engine compartment on the passenger side mounted to the firewall, that controlls the blower motor. The connections may have corroted or the unit itself is bad. That was the first thing I had to relpace when I got my used 92 Dakota. There is also a 30 amp fuse in the fuse box under the dash board . If that is blown I would suspect the blower motor is seized up or just pulling too much power.

you say it will blow cold and hot air for only a few minutes. You don't say but I assume you mean will blow cold a few min. when turned on AC max , blow hot only a few min. when turned to heater hot. Assuming thats the situation and you say AC charged and shows good on the low side -you should charge the AC to a full charge on the low side will cause problems with the AC air compressor kicking on and off. I suggest while the engine is running and turned to AC cold max watch the AC air compressor clutch to see if it does indeed kick on and off if so charge completely. As far as the heater make certain you coolant is all the way to the top and the best way to do this is when engine is completely cold remove radiator cap and fill completely and completely close cap then fill overflow container just to the cold level. That should fix your problem.

Take a look under the dash at the heater/ac blend door(s) and cycle hot to cold on he dash heat control while asking for AC and the vehicle running.Do the doors move fully?
You may be able to manually help the door move to get cold air.

I have a 2000 pontiac grand prix with a digital climate control system. The heat quit working, it doesn't blow out any heat. Now that it is warm outside the air stopped blowing out any air. The digital temperature on the climate control is not correct. When it states that it is below 30 degrees on the ext and it is warm outside the air wont be cold. Once it starts going above 30 degrees the air gets colder. Today the blower stop working all together. Was told it maybe the climate control unit was bad. You can hear the door opening/shutting when you switch the temp from cold to hot. But there was no heat blowing out whatsoever in the winter time. Could you please give me your opinion on whether or not it is the climate control unit or something else?

Check the A.C>Relay or It could be low or leaking freon

Ok it may be that the heater core bypass valve isnt opening. All that valve dose is when you turn the climate control to heat it opens a valve that allows hot coolant from the engine to flow through the heater core. What I would do is check that. It will be on the left side (passange) of your engine bay.You will see two black coolant hoses next to eachother and one will have a black box with a wire that runs to it. Have someone move the climate control from hot to cold to hot back to cold. If you dont see the wire move then you can move it yourself to open the valve.

Let me know if the valve opens or not using the climate control.

check freon in system if not enough freon compressor wont kick in