GM Service Manual Online
For 1990-2009 cars only

The A/C system has a pressure sensor mounted on the compressor/condenser hose assembly near the condenser connection. The sensor performs the following functions through an input to the PCM:

    • Low pressure cutout
    • High pressure cutout

The system does not use compressor mounted switches. The sensor is mounted on a service fitting. You may replace the sensor without discharging the A/C system. Refer to HVAC Blower Controls Circuit Description for more information.

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Disconnect the electrical connection at the sensor.

  3. Object Number: 277955  Size: SH

    Important: The sensor is mounted on a service fitting. Do not discharge the system.

  4. Remove the pressure sensor.
  5. Discard the O-ring seal.

Installation Procedure

  1. Lubricate the new O-ring seal in clean 525 viscosity refrigerant oil.
  2. Install the new O-ring seal.

  3. Object Number: 277955  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  4. Install the pressure sensor (9).
  5. Tighten
    Tighten the sensor to 5 N·m (44 lb in).

  6. Connect the electrical connection at the sensor.
  7. Connect the negative battery cable.
  8. Tighten
    Tighten the bolt to 16 N·m (12 lb ft).