A/C On/Request Signal
WARNING: This page is about a different car, the 2003 Saturn LW300 and 2003 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.
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 ECM. The ECM 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. ECM activates 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 TESTING - 3.0L SATURN "L" SERIES article.