Conditions for Setting the DTC

WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

When the BCM receives a instrument panel controls illumination lamp request signal and the instrument panel lamps dimming control circuit is shorted to ground.
When the BCM is not receiving a instrument panel controls illumination lamp request signal and the instrument panel lamps dimming control circuit is shorted to voltage or open.