A/C compressor does not come on 2000 Grand Prix

Could be air in the cooling system , try an bleed the system . On top of the thermostat housing is a bleeder valve , with the engine up to temp. open valve till coolant comes out . Is the coolant full ? What color is the coolant ? Have see where coolant turns like a muddy color an clogges the heater core an engine coolant passages . Check the heater hoses going into the fire wall ,are they hot ? Does your grand prix have manual or automatic climate control ? Duel zone ! Do you hear a clicking sound behind the instrument panel ? Bad temp blend auctuator .

it could just need to be serviced. on most cars your age or newer, if it doesnt sense any pressure from the pressure switch that the system is charged it wont engage the a/c pump

u may have the gass leak of a.c . fill up the gas an for heate check the mixture pipes ..they may b direct..

Check that the AC compressor clutch is engaging. It is electromagnetic and is also prone to seizing from corrosion. Sometimes simply giving it a firm tap and some lubricant can solve it.

find the high pressure switch,pull plug off jump it there,,if u are trying to see if compressor works,,most compressors will on engage if there is no pressure,,,

With regards to you a/c not blowing cold there are several faults that could cause this. Your compressor may not be working, they may be a restriction in your A/C lines, your compressor and/or evaporator may be clogged, you may have a leak, or i could be something as simple as fuse.

check the temp control switch in the dash

orfice tube stoped up or make shure motor electric fan comes on when u cut ur ac on with motor runing

Damper/flap for driver's side is probably stuck. Try moving the selector from cold to hot several times. Also, move the recirc/outside air control if the previous doesn't work.

this is most likely a a lack of r-134a (as freon is no longer used), if your system is completely out or close to it then the pressure sensor will not allow the compressor clutch to engage, it is also possible that there is an electrical issue but less likely. to know for sure you need to put some gauges on the system