2000 C5, after pulling a vacuum on the AC, no leaks, I used the vacuum to load a can of freon, so there is freon in the system. I can not get the clutch to engage. I know there is a high side sensor for freon pressure, is there a low side sensor? Is there a special way to engage the clutch. Am I missing something?? Any suggestions would be greatly appreciated.. I live in Texas and it is HOT.

Help me get my C5 cold again.

Thanks
raiderman444

 

Let us know what you find.

 

did ya check power and ground at the compressor? maybe its just a bad clutch would check there first and work my way backword

 

not sure what you mean by sensor but there is of course a high and low valve one has a cap that is black and one that is blue. IS this what you mean?

 

There is a low pressure sensor that will prevent the compressor from coming on in the event that there is not sufficient pressure to run the compressor without risking damage. On my 2002, it is on the low pressure line coming from the condenser and has 2 wires going to it. If you know that you have sufficient pressure in your lines, you should be able to short those 2 wires together and see if the compressor comes on. From there, the wires go the the side of the compressor just behind the clutch. Make sure it's plugged in there. If you short the wires going to the switch and the compressor comes on and you also have good line pressure then that switch is defective and simply needs to be replaced. Also, not sure what fuse it is, but you could have one out under the hood or in the passenger floor. You can get a volt meter and make sure when you have the A/C on that you have voltage going to the low pressure switch. If not, you have a broken circuit somewhere. Blown fuse, open connector, defective A/C switch etc.

 

Hi, the vette system needs 28 oz. of refrigerant 134a. If you got a whole can in, the cans are usually 14 oz., so you need another can. Also you should add at least 3 oz. of the proper oil,(pag), because you lost at least that much with the old refrigerant that either leaked out or you evacuated . The system needs to see at least 30psi for the comp to start. The one pressure switch is a combined low, and high pressure switch, and sits on the thin line that comes from the evaporator, it has a connector with 2 wires on it. There is a fuse #24 -10 amps in the underhood fuse box,(check it), and a micro relay #34 same place. Hook up the second can of refrigerant, and place the can about 3/4 of the length, not to the top in a pail of warm some what hot water,(do not get any water into the system), this will help it flow in to the system. Turn on the AC, set the temps to max cold, (60 on the auto system), if the system doesn't start up you can turn the can upside down for a few seconds untill the comp kicks in , then turn it right side up and place it back in the warm water, (I know some will say don't add ref with an upside can because it sends liquid into the compressor stressing the valves, but you are just doing it enough to get enough pressure in to the system to get it to run on its own, and then turning it right side up). Then the compressor will cycle on and off untill it has enough pressure in it to run steadily. You need to get both full cans and the oil in for the most efficient cooling. If it still will not start using the above method, you can ground the coil side of the relay to run it.
Hope this helps
Good Luck
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A/C Pressure Sensor
The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5-volt reference, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0-5 volts. When the A/C refrigerant pressure is low, the signal value is near 0 volts. When the A/C refrigerant pressure is high, the signal value is near 5 volts. The PCM converts the voltage signal to a pressure value. Shorting the wires on the pressure sensor connector should not make the compressor run, because it will send a 5 volt signal to the pcm signifying high pressure which will keep the comp from running. The older type pressure switch was an off/on switch, these new types are a value switch sending a reference value to the computer that the computer interprets and acts accordingly..

The A/C system can be engaged by pressing the A/C switch. The A/C switch will illuminate when the A/C switch is pressed to the on position. Pressing the A/C switch the control module grounds A/C request signal circuit from the powertrain control module (PCM). The following conditions must be obtained before A/C compressor engagement is allowed:

The engine coolant temperature (ECT) is less than 121°C (250°F)
The engine RPM is more than 550 RPM
The A/C pressure is between 207 kPa (30 psi) and 2826 kPa (410 psi)
The A/C request signal circuit is grounded.
Once engaged, the compressor clutch will be disengaged for the following conditions:

The throttle position is 100 percent
The A/C pressure is more than 2826 kPa (410 psi)
The A/C pressure is less than 207 kPa (30 psi)
The engine coolant temperature (ECT) is more than 121°C (250°F)
The engine speed is more than 5,500 RPM
The transmission shift
The PCM detects excessive torque load
The PCM detects insufficient idle quality
The PCM detects a hard launch condition
When the compressor clutch disengages, the compressor clutch diode protects the electrical system from a voltage spike.

 

Thank you so much for your ideas, I really appreciate it. I will let you know what I come up with.

raiderman444

 

thanks so much for the info, I will try your suggestions and let you know.

Thanks
raiderman444

 

Did you clear your codes?