When I remove the a/c relay and jumper the connection my a/c compressor clutch kicks in. When I removed this jumper the compressor will not engage. Is there a sensor or a switch located that controls this. Also, the relay is good.

Hi Adeyeri

Keep in mind that the Clutch won't engage for a few safety reasons.

Temperature inside vehicle
Temperature of compressor or pipes
Pressure inside pipes
Compressor jambed
Eg It's out of refrigerant Gas

You can momentarily engage the clutch by simply giving it +12v to the wire attached to clutch. Usually has a connector close by.
Or
If it has a Relay (click) in fuse box
You can by pass it with a jumper

A quick engage & disengage should allow you to detect possible problem.
But don't over ride the built in safety for more than about a minute.

Cheers
Hope this Helps

Vehicle Air Con testing YouTube

FIXED Car Compressor Clutch Won Engage

12 Volt Car Relays Used In Automotive Industry

How do you know the freon charge is not low ?
If the system is full, you should be able to jumper the relay and make the compressor clutch engage.
If not, the problem could be the low pressure switch or the clutch.

The relay is under a black plastic cover on the driver's side behind the battery. There are a couple other relays under there.-------I would start by jumping the AC relay to see if the clutch will run, you do this by removing the relay and putting a jumper wire between 30 and 87 terminals, if the clutch runs then check to see if there is power on the 85 terminal at the relay and a ground at terminal 86 if all are good replace the relay. The terminal numbers are located on the bottom of the relay, be sure that terminal 30 has power if the clutch does not run.
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Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.
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This will solve the problem or point you towards the cause of problem. Thank you for using fixya.

Since you know that the clutch must engage in order for the compressor to operate, then there are most likely one of causes. The first is low or no freon in the system. The a/c system has a pressure sensor mounted in the low( return) side hose that prevents the clutch to engage if the freon is too low. The second would be the a/c fuse or relay faulty, preventing the clutch solenoid( a 12 volt electrically operated solenoid) from engaging. And the third would be that the clutch itself is bad because the solenoid wiring has broken. I suggest that first you locate the a/c clutch relay in the relay panel, remove the relay, carefully remove the plastic cover from the relay and reinstall the relay. The clutch should engage the compressor when you manually close the relay contact with your finger for one or two seconds. If the clutch does engage, your electrical circuit in ok and you are probably low on freon. A half of a can of r-134 in more that enough to operate the pressure switch. If it doesn't engage, check the a/c fuse or the clutch solenoid itself. Get back to me and let me know how things went. Dano

If the compressor kick's in when you jumper the relay socket there is no problem with the electrical to the compressor an the compressor isn't locked up . You have a control side problem , the PCM - engine computer is suppose to energize the relay if no other problems are present . The proper way to check this would be to hook up a scan tool an check pressure input's to the PCM an is the PCM getting a request from the HVAC control panel to turn on the A/C compressor . AutoZone is wrong as usual , There can be codes without the check engine light being on . o'reilly's is wrong as well DTC P0530 (LU3, LR4, LM7, LQ4 and L18)
The powertrain control module (PCM) or engine control module (ECM) monitors the high side refrigerant pressure via a A/C refrigerant pressure sensor. When the pressure is high the signal voltage is high. When the pressure is low the signal voltage is low. When pressure is too high the PCM will not allow the A/C compressor clutch to engage.

Action Taken When the DTC Sets
The malfunction indicator lamp (MIL) will not illuminate.
Diagnostic Aids
The air conditioning (A/C) compressor clutch will not engage under the following conditions:
• The A/C high side line pressure is over 2957 kPa (429 psi).
• The A/C low side line pressure is under 138-172 kPa (20-25 psi).
• Throttle angle is at 100 percent.
• Engine speed is more than 5500 RPM.
• Engine coolant temperature (ECT) is more than 121°C (250°F).
• Ambient air temperature is less than 5°C (40°F).
• Engine is idling at a low unstable RPM
Compressor clutch engagement cannot be used to determine status of the low pressure switch. The low pressure switch is one of several inputs to the HVAC control module for A/C request authorization. A/C request is one of several inputs to the powertrain control module (PCM) that control A/C compressor clutch engagement.
To accurately determine what pressure the A/C low pressure switch opens and closes at use Kent Moore GE-47742 which will allow the technician to measure the switch point pressure at the switch.
Using a scan tool, monitor the "low pressure switch" status while monitoring the "low side" pressure at the switch to determine the switch points of the low pressure switch.
The low pressure switch "connector seal" must be removed before plugging it into the switch for testing. The "plunger effect" of plugging the connector with seal into the switch induces a pressure on the back side of the switch, this pressure will skew the opening/closing characteristics of the switch 5-10 psi until the pressure bleeds off. The time required for the connection induced pressure to bleed off can take 20 minutes or longer

Do you have the proper diagnostic tools ? Factory scan tool , A/C gauges ? You best bet , take your vehicle to a qualified repair shop !!

You can make your compressor come on manually by putting a jumper
in the wiring connector going to the evaporator. It's the 2 wire plug.
If you foolw the wiring from the compressor,you should be able to
figure out where the wiring is. Just remove the plug and put a jumper wire across the terminals to get the compressor clutch to engage and
make the compressor pump.Good luck.

take the pressure switch connector off and jump connector- if clutch engauges you either have bad low pressure switch or are low on freon.

I would check the pressure on the system first. If you have a leak in the system the pressure will drop and keep the compressor from cycling on ( keeps you from burning up the compressor) If the system is indeed holding pressure, the problem can be a compressor relay, on GM products this is normally under the hood close to the firewall. It also can be the A/C control module not funtioning. (Not sending voltage to the compressor clutch) On many of the newer systems the components( ie: clutch, hi-pressure switch, low pressure switch, relays) are already energized and the control module just completes the circuit to ground. In other words when you check for voltage at these items it will be present, even though the unit may not be engaged.

if compressor clutch dont kick in .it has a open in clutch coil.

I AMA MASTER VOLVO ASE TECH AND RUN A JUMPER WIRE FROM A/C COMPRESSOR WITH A/C ON MAX TO POS BATTERY AND SEE IF COMPRESSOR CLICKS ON AND IF A/C RELAY GETS HOT IT IS POSSIBLE A BAD COMPRESSOR OR DOES THE FAN COME ON WITH A/C ENGAGED THE FAN IS A TWO STAGE UNIT ON 850,S ONE IS THE ENGINE TEMP RED AND THE GREEN IS FORTH A/C SYSTEM