Should the AC compressor clutch engage when the

Sounds like a couple of problems. First check the fan motor . Does it turn freely while off? Check for power to motor. Check to make sure the heater valve is closing when ac is on. Block one of the heater hoses to check.
Make sure the compressor is turning at higher rpms.

Knowing make model and year would help. Most newer vehicles, 2000 and newer, will adjust the idle control up to compensate for the compressor engaging. Possible there is an issue in the idle air control valve or electrical circuit.

have the AC tech performed a leak test on the system after recharging? is the expansion valve and filter drier as well as the o-rings for the fittings replaced? check also for possible leaks in the system in the fittings of the hose and in the evaporator housing. also check if the magnetic clutch of the AC compressor is engaged, you will hear a click when it it engaged.

There is a wiring connection at the A/C clutch that once disconnected will not allow the compressor to engage.

Locate wires coming from compressor clutch and trace to nearest plug that you can unplug. Turn on A/C to max cooling. If clutch not engaged (center of compressor drive pulley not spinning with pulley), unplug compressor clutch wires and use multimeter to check voltage going to compressor clutch. If voltage is around 12 volts or more, then clutch should be engaged when plugged in. Plug clutch wires back in (with motor still running and ac set to max). If clutch still not engaged, then clutch definitely bad because 12V signal should engage it.

could be your ac compressor kicking in and out.turn off all your climate controls and see if it dosent stop. you can also lift your hood and watch youcompressure to see if the clutch is engageing

Hi...
Perform the following basic Checks and Information
1. Check Drive Belts,If belt is intact proceed to the next step.
2. Check for Compressor Clutch Engagement - Turn the air conditioner to the "on" position and set controls to the coldest setting. Start the engine and allow to idle. Then open the hood and inspect the clutch at the front of the compressor, is it turning? "Engaged" if so, the system has enough refrigerant to activate. If the system is low on refrigerant it will not work properly. In this case an air conditioner recharge kit is needed to recharge the system. If the compressor clutch is not turning proceed to next step.
3. Inspect for Refrigerant Leaks
4. Check under dash panel and under hood power distribution center
5. Check Temperature Control Vents - The vents inside your car are controlled by a cable, electrical servo or vacuum servo. If the vent door is not functioning properly it will cause warm air from the heater to exit the vents. To check this start the car and allow the engine idle, next turn the blower motor speed on low, switch the temperature control from warm to cold while your ear is close to the vents. You should hear the door move inside the heater box as it swings from open to close. If not, inspect for a vacuum leak or a shorted motor in the servo, repair the leak or replace the servo motor.
Thanks
Smith

start car.turn on air conditioner high cool .raise hood look to see if the compressor clutch is engaged and running.if yes your ac air door could be stuck closed or the air door vacuum actutator not receiving vacuum.a vacuum line is broken or off. or the control switch bad.that control the AC and heater mode. if compressor clutch is not engagged.check for power at compressor clutch.if yes compressor clutch coil open. or the air conditioner refrigerant R 134 is low take car to a private garage with a good reputation. they wont be expensive as the dealership.have them hook car air conditioner to a manifold gauge set to check your refrigerant low side and high side pressure.

If your R 134 is low in your system then the AC compressor will not engage the clutch to run the compressor. Have your system check for charge level of the R134 first. If low they can add to system. All AC systems leak down over a period of time and need to be recharged. So, don't get worried that your system is bad. If the charge depletes itself again quickly then you have a leak somewhere in the system that needs to be addressed.

Hi

This could be any number of things, low system pressure, chattering relay, faulty cycling switch, failed compressor, poor cooling, the list goes on.

I'm afraid this is a job for the professionals!

Very best regards

Geordie