A/C is weird

[UsMuScL398]

Ive figured it out to this part....my a/c does work, it does not work upon starting car....i have to rev the car to just around 4k to get it to kick in and only there will it engauge....it does peridicly just stop, but probably when i get on it. But does anyone know why it would come ON at a certian rpm?

[nikon]

it should only turn off above 4k or wot most of the GM's do it, if not all of them

[Pastor Larry Roques]

have you checked the R-134 levels. These guys are equipped with a pressure switch that protects the compressor. If it is low on refrigerant, it will not run. Just thinking out loud...the increased rpms of the engine would cause the refrigerant to move through the system faster triggering the switch...even a slightly deficient refrigerant level could produce these results. It happened on my mini-van and it took me a while to figure it out! Blessings

[UsMuScL398]

nah its full i just put some in....The a/c is very cold when its on

[chas]

perhaps the pressure switch is bad (or the wiring to the pressure switch -- but that less likely). anyway the a/c will cycle on run for a short bit and then check the pressure switch. if there wasnt any pressure (low freon or bad pressure switch) it will cycle off so that the compressor will not burn up.

the pressure switch should be located near the a/c dryer if i remeber correctly.