For 1990-2009 cars only
Relays and Sensors Description for Buick Park Avenue 1999
A/C Compressor Control Relay
The A/C compressor control relay cycles the compressor on and off by energizing and de-energizing the compressor clutch coil.
With the ignition key on, a current of 12 volts is applied to the relay common contact and one coil terminal. The PCM grounds the second coil terminal under the following conditions:
| • | When the driver selects A/C mode |
| • | When the driver selects defrost mode |
| • | When all other requirements are met |
When the relay is energized, current passes through the relay contacts. This action energizes the compressor clutch coil.
