A/C cuts out when engine reaches normal temp

[Todd Pelton]

Hello!
I was hoping someone either had a similar problem or had an an answer to this problem I have with my 1995 4Runner. I've had it for 5 months and love it but the A/C goes out just after the engine gets to normal operating temperature. I bought the vehicle from someone in Denver, CO and moved it here in mid-winter. It had always been in the Denver area and the A/C system probably didn't get much use. The high and low side pressures are very normal when it is operating. I did some previous research and checked to make sure the water temp switch was grounded, replaced the expansion valve on the evaporator and replaced the receiver drier at the same time. I've tested the relays and the resistance was normal. It is like clock work though, 3-5 minutes after the engine reaches normal operating temp the A/C just stops working. I'm convinced it has to do with the water temp switch because it looks like it's tied in on the wiring diagram. Any suggestions would be greatly appreciated. Thank you. Todd - Oklahoma

 

[RotaMan2]

Does the idle drop when it reaches normal temp.? If so, make an adjustment on the A/C idle control valve, located on the passerger fender well.

 

[Todd Pelton]

Thank you for the suggestion.

 

[4theweekend]

If the ac compressor is still working when warmed up, check your heater core water shut off valve. Sounds like it's not stopping the flow of water. So once the engine is up to temp the heater core is too, heating the air after it leaves the evaporator. The fan is always blowing air through both cores, it blows to the evap first then to the heater.

To check valve, slide the lever to cold and feel each side of the valve for heat once the engine is warmed up. One side should be cool, if not pinch the hose and see if that works.

 

[Todd Pelton]

Thank you for the suggestion. I ended up replacing the a/c amplifier 5 days ago and haven't had any problems with the a/c. I will keep this in mind if the problem returns. Thanks again.