For 1990-2009 cars

#### Body Control Module (BCM)

Scan Tool Parameter | Additional Menu Selection(s) | Units Displayed | Typical Data Value
--- | --- | --- | ---
Operating Conditions: Ignition ON, Engine OFF.
Battery Voltage Signal | HVAC/Data Display/BCM/HVAC Data | Volts | 13.5 Volts
Rear Defog Relay Cmd. | HVAC/Data Display/BCM/HVAC Data | On/Off | Off
Rear Defog Switch | HVAC/Data Display/BCM/HVAC Data | On/Off | Off