Buick Century 2003 Air Condition Does Not Work

[tlijun]

My buick century 2003 air condition does not work. check the refrigerant pressure, it is very very low, and needs refill refrigerant. Becuse the refrigerant pressure is low, the compressor clutch does not engage. Can someone tell me where the refrigerant low-pressure switch electrical connector is? I am trying to short the refrigerant low-pressure switch to directly engage the compressor clutch.

Thanks your help in adcance.

[BNaylor]

The pressure switch is a high and low pressure switch. You cannot jump it with a straight wire jumper like older A/C systems. A resistor representing pressure between the low and high pressure thresholds has to be used so the PCM module can energize the A/C clutch relay. The switch should be located at the driver's side of engine compartment by the accumulator.

[tlijun]

Thanks bnaylor.

I have located the switch there are three wires in it. If I cannot jump it with a straight wire jumper like older A/C systems, do you know how I can energize the A/C clutch relay? I saw two wires connect to the compressor, can I disconnect the plug and directly apply the 12 volts to the compressor?

[BNaylor]

You're welcome.

You could apply a jumper at the A/C Clutch Relay socket side. Pull the relay and on the side you should see a diagram of the coil contacts and the NC/NO (normally open or normally closed) contacts. Jump the points that match up on the relay to the socket. You can jump the two pins of the NC/NO contacts at the socket part or apply 12 volts and/or ground to the relay coil. One side of the coil is the ground/low from the PCM module to get the compressor clutch to engage. Other side 12 volts which should be there at ignition to ON.

For example on most relays used by GM pins 86 and 85 are the relay coil contacts. Pins 87 and 30 the NC/NO contacts.