My air conditioner starts out blowing cold air, but if a change is made with the temperature knob, fan knob, or even the position of the air vents the air condition starts blowing hot air. If I turn the ait conditioner off and wait awhile the air conditioner will again blow cold air. Can you tell me what the problem might be?

SOURCE: 1998 Volvo V70 A/C Intermittent

I had exactly the same problem. When your engine is cold and off check the gap on your ac compressor with a feeler gauge, it should be between 0.3 and 0.5mm. If it is larger you need to re-shim which invloves undoing a nut on the end off the compressor and removing the clutch plate, then removing the appropriate shims (look like washers) then replace. The reason it blows warm after 10 minutes or so is because the ac compressor gets hot and the clutch gap gets too large for the electro-magnetic clutch to engage. Some people would say that you need a new compressor but all you need to do is a re-shim.

SOURCE: a/c blows cold then goes to hot air

sounds like a vaccum diaphram may be leaking try listening for hissing noises under dash near the glove box,set blower to lowest setting\off if you can and still have a\c on.

SOURCE: 1998 Volvo V70 A/C intermittent

I AM AN ASE CERTIFIED VOLVO----MASTER TECH AND YOUR PROBLEM W`HICH IS COMMON ON ALL 850,S ANDS70,S THE PROBLEM IS PROBALLY AT LEAST 70% DUE TO AN AIR-FLOW RISTRICTION TO THE CONDENSOR FIRST IS SYSTEM AT FULL CHARGE LOW SIDE 25-33 PSI AND YOU AND I REPEAT ONLY CHARGE SYSTEM ON THE LOW SIDE THERE IS NO AND I REPEAT NO HIGH PRESSURE CONNECTOR AND WHAT I WOULD DO IS RUN AGOOD THICK WIRE FROM A/C COMPRESSOR AND A 30 AMP FUSE FROM A CIRCUIT LIKE THE HEATED SEATS FROM INSIDE THE CAR WITH A TOGGLE SWITCH AND A THERMOMETER IN CENTER AIR DUCT AND MANUALLY SHUT THE SYSTEM DOWN IF IT FALLS BELOW 40 DEGREES AND WATCH THE THERMOMETER EVERY 7 MINUTES AND THE MAIN PROBLEM IS THE ENGINE FAN CIRCUIT I HAVE DONE DOZENS OF THESE AND THE PROCEDURE IS WHAT I WROTE

SOURCE: no air or heat blowing from vents

if the fan is blowing this could be a problem with the climate controll switch that changes the direction of air from floor to defrost to vents, some are vacuum controlled through a vacuum operated mechanism that opens and closes a door in the vents which redirects the air to different places.

SOURCE: Air conditioner works then stops blowing cold air

when you day the air goes on and off i assume you mean the compressor goes on and off. that is what moves th freon through the system. if you are getting cold air when the compressor is running then the problem is that the compressor is stopping and that would be because a pressure switch may be bad. it is possible that model has a thermal shut down too say if the compressor was low on lubricant and was overheating when it does run. but if it is a pressure switch that is failing and they do, it is an easy fix. if you follow the ac lines you will find the switch.it is small about the size of a sparkplug-attached to the ac line and will have a connector with two wires. if the car is running and ac is on but the compressor is not turning remove the connector and jump to two wires. the compressor will start running if the switch was bad and we are sure there is a good charge on the system. if you are getting cold air there should be a sufficient charge to close the switch. these switches can be removed without losing any freon. there is a valve below them that will shut off when the switch is removed. then all you have to do is get a new one and screw it into place,apply the connector and you are done. if that is the problem. hope this helps please let me know and good luck

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