For 1990-2009 cars

Table 1: | Body Control Module (BCM)
Table 2: | Heater and AC Control Module (HVAC)

#### Body Control Module (BCM)

Scan Tool Parameter | Data List | Units Displayed | Typical Data Value
--- | --- | --- | ---
Ignition ON/Engine OFF
Courtesy Switch | Input | ON/OFF | OFF
Delay Interior Output | Output | ON/OFF | ON
Door Jamb Switch | Input | ON/OFF | OFF
D.R.L. Output | Output | ON/OFF | OFF
Exterior Lamp Output | Output | ON/OFF | ON
Low Beam Output | Output | ON/OFF | OFF
Headlamp Required Output | Output | ON/OFF | OFF
Head Lamp Switch | Input | ON/OFF | OFF
Highbeam Switch | Input | ON/OFF | OFF
High Beam Output | Output | ON/OFF | OFF
Interior Lamp Output | Output | ON/OFF | OFF
Park Lamp Switch | Input | ON/OFF | OFF
Park Position Input | Input | In Park/Out of Park | In Park
Park Lamp Relay Output | Output | ON/OFF | OFF
Trunk Jamb Switch | Input | ON/OFF | OFF
Twilight Lamp Output | Output | ON/OFF | ON

#### Heater and AC Control Module (HVAC)

Scan Tool Parameter | Data List | Units Displayed | Typical Data Value
--- | --- | --- | ---
Ignition ON/Engine OFF
Twilight Sensor Voltage | Input | Volts | 4.1Volts