Circuit/System Description

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The body control module (BCM) supplies voltage to the HVAC module and the windshield washer solvent heater (RPO XA7), and the control circuit of the RUN PCB relay (TP2) through the ignition 3 voltage circuit. voltage is applied when any of the following conditions are true:

Ignition Switch is in ACC or RUN.
The vehicle was remote started.
The vehicle is in retained accessory power (RAP) mode.