GM Service Manual Online
For 1990-2009 cars only

Hi-Blower Motor Relay

The hi-blower motor relay provides battery voltage to the blower motor only during high blower motor assembly speed. The hi-blower motor resistor provides reduced voltage to the blower motor assembly in all other speed settings. The hi-blower motor relay is located on the cowl side of the engine compartment. The hi-blower motor relay is the first relay on the right side.

Compressor Relay

The compressor relay provides battery voltage to the compressor clutch coil. The Engine Control Module (ECM) controls the relay. The compressor relay is located next to the hi-blower relay. The compressor relay is the second relay from the right.

High Pressure Cutout Switch

The compressor is equipped with a high pressure cutout switch. This switch is normally closed. The switch opens in order to interrupt the voltage to the compressor clutch coil. This causes the following conditions:

    • The compressor does not cycle.
    • The pressure relief valve does not discharge refrigerant and oil.

Low Pressure Cutout Switch

The low pressure cutout switch protects the compressor. The low pressure cutout switch opens in the event of a low-charge condition. The switch is located in the rear of the compressor.