A/C On/Request Signal

The A/C power switch is mounted in the instrument panel. This switch provides a simple "on" (A/C request) signal, which is monitored by the PCM. The PCM uses this signal to determine control of the A/C clutch relay (if equipped) and to adjust idle speed when A/C compressor clutch is engaged. Control unit also activates radiator cooling fan when this signal is present. If this signal is not present on A/C equipped vehicles, engine may idle rough when A/C compressor cycles.