Relays and Switches

Blower Motor Relay

The blower motor relay is used to provide battery voltage to the blower motor only during high blower motor speed. The blower motor resistor is used to provide power to the blower motor in all other speed settings. The blower motor relay is located under the instrument panel.

Air Conditioning Compressor Relay

The air conditioning compressor relay is used to provide battery voltage to the compressor clutch coil. The relay is controlled by the powertrain control module (PCM) only. The relay is located in the underhood electrical center.

Air Conditioning Refrigerant Pressure Sensor

An electronic A/C refrigerant pressure sensor is mounted in the evaporator tube between the evaporator and the condenser. The sensor output to the PCM is variable and is dependent upon pressure inside the line. A high line pressure results in a higher voltage output. The PCM constantly monitors the A/C refrigerant pressure in order to perform the following functions:

^ Disengage the A/C clutch if the pressures are above 2826 kPa (410 psi)
^ Disengage the A/C clutch if the pressures are below 207 kPa (30 psi)
^ Boost idle air control to compensate for A/C load at idle
^ Cooling fan control
If the sensor fails, the sensor must be replaced.