Inside Rearview Mirror Reading Lamps

Voltage is supplied to the inside rearview mirror reading lamps from CKT 640. CKT 640 receives battery voltage when the MONITORED LD Micro Relay #43 has closed its contact switch. The opening and closing of the MONITORED LD Micro Relay #43 is controlled by the BCM through CKT 1393. Whenever the ignition is ON the BCM will ground CKT 1393 and energize the relay which supplies battery positive voltage to CKT 640. Battery voltage is then supplied to the inside rearview mirror reading lamps and they becomes functional. When the ignition is turned OFF the BCM will monitor CKT 640 at the BCM connector C2 terminal C4 for continuity to ground through the inside rearview mirror reading lamp and switch assembly. In the event that an inside rearview mirror reading lamp is inadvertently left ON, the BCM will energize the MONITORED LD Micro Relay #43 for approximately 15 minutesthen de-energize the relay. This function is used to help prevent the battery from losing voltage over a period of time in the case of a load being left ON. The inside rearview mirror reading lamps are grounded by CKT 150 through Splice Pack #202 to G202.