A/C On (A/C Request) Signal

The air conditioner "on" switch is mounted in instrument panel. This switch provides a simple "on"("A/C request") signal, which is monitored by control module. The control module uses this signal to determine control of the A/C clutch relay (if equipped) and to adjust idle speed when air conditioner compressor clutch is engaged. On FWD Vans, control unit also activate radiator cooling fan when this signal is present. If this signal is not present on A/C equipped vehicles, vehicle may idle rough when A/C compressor cycles. To check function of the A/C switch, perform functional check of switch. See SYSTEM/COMPONENT TESTS - 5.7L article.