Conditions for Running the DTC

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Source voltage is 8.7-16.5 volts.
The HVAC control module receives a RUN power mode message from the BCM over the class 2 serial data circuit.