Hummer H2. Manual - part 307

SCAN TOOL OUTPUT CONTROLS 

Body Control Module (BCM) 

SCAN TOOL DATA LIST 

Body Control Module (BCM) 

5

begin with a U ?

Not Communicate 

with Class 2 Device in 

Data Link 

Communications

Go to Step 6

6

Does the scan tool display DTC B1000, B1004, 
B1007, B1009, B1397, B1420, or B1440?

Go to Diagnostic 

Trouble Code (DTC) 

List in Body Control 

System

Go to Diagnostic 

Trouble Code (DTC) 

List

Scan Tool 

Output 

Control

Additional 

Menu 

Selection(s)

Description

Light Test

Daytime 
Running 
Lamps

The BCM activates the DRL relay when there is sufficient light to the 
ambient light sensor and you select ON. The daytime running lights 
will remain illuminated until commanded OFF.

Light Test

Parking Lamps

The BCM activates the park lamp relay when you select ON. The park 
lamps illuminate until commanded OFF.

Light Test

Backup Lamps

The BCM illuminates the backup lamps when you select ON. The 
backup lamps will remain ON until commanded OFF.

Lamp 
Dimming Test

Dimming

The BCM adjusts the dimming output level when you select the 
percentage of illumination desired. The dimmable I/P lamps will 
illuminate to the level set by the scan tool when the I/P dimmer switch 
is in the FULL DIM position and remain until commanded ON.

Inadvertent 
Power

 

The BCM deactivates the inadvertent power circuit when you select 
OFF. The inadvertent power circuit will remain inactive until 
commanded ON.

Scan Tool Parameter

Data 

List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Vehicle in PARK/Park brake RELEASED/Headlamps in AUTO/All 

doors/tailgate closed

Backlight Dimming

Data

Percent

Varies

Backup Lamps

Output

On/Off

Off

Backup Light Request

Input

Active/Inactive

Inactive

Battery Voltage

Data

Volts

Varies

Courtesy Lamp Relay

Input

On/Off

Off

Courtesy Lamp Switch

Input

Active/Inactive

Inactive

Daytime Running Lamps

Output

Active/Inactive

Varies

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

Driver Door Module (DDM) 

Passenger Door Module (PDM) 

Dimming Input

Data

Volts

Varies

Dimming Potentiometer

Data

Volt

5.0

DRL Disable Switch

Input

Active/Inactive

Inactive

Flash to Pass Switch

Input

On/Off

Off

Front Wipers Active

Input

Yes/No

No

Headlamp Switch

Input

Active/Inactive

Inactive

High Beam Relay

Output

On/Off

Off

High Beam Switch

Input

On/Off

Off

Ignition 0

Input

On/Off

On

Ignition 1

Input

On/Off

On

Ignition Accessory

Input

Active/Inactive

Active

Inadvertent Power Relay

Input

On/Off

On

Indicator Dimming

Data

Percent

Varies

Interior Lamp Defeat 

Switch

Input

On/Off

On/Off

Left Rear Door Ajar 

Switch

Input

On/Off

Off

Light Sensor

Data

Volts

1.75 Volts Maximum Light to 4.9 Volts 

Maximum Dark

Park Lamp Relay

Output

On/Off

On/Off

Park Lamp Switch

Input

Active/Inactive

Inactive

Right Rear Door Ajar Sw

Input

On/Off

Off

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Vehicle in PARK/Park brake RELEASED/Headlamps in AUTO/All 

doors/tailgate closed

Dimming Enable

Input

On/Off

Off

Dimming Potentiometer

Data

Percent

Varies

Door Ajar Switch

Input

On/Off

Off

Memory Switch Backlight

Data

Percent

Varies

Window Switch Backlight

Data

Percent

Varies

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Vehicle in PARK/Park brake RELEASED/Headlamps in AUTO/All 

doors/tailgate closed

Backlight Dimming Enable

Output

Yes/No

Yes

Dimming Enable

Input

On/Off

On

Dimming Potentiometer

Data

Percent

Varies

Door Ajar Switch

Input

On/Off

Off

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

Instrument Panel Cluster Module (IPC) 

SCAN TOOL DATA DEFINITIONS 

Data 

Backlight Dimming  

The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM 
to the PWM controlled I/P backlighting based on the position of the I/P dimmer switch, thumbwheel. 

Battery Voltage  

The scan tool displays the battery system voltage received by the module. 

Dimming Input  

The scan tool displays the voltage value indicating the position of the I/P dimmer switch, thumbwheel. 
The scan tool displays 4 volts when the I/P dimmer switch is in the FULL DIM position. The scan tool 
displays 0 volts when the I/P dimmer switch is in the FULL BRIGHT position. 

Dimming Potentiometer  

The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM 
to the PWM controlled door switch backlighting based on the position of the I/P dimmer switch, 
thumbwheel. 

Indicator Dimming  

The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM 
to the PWM controlled I/P backlighting based on the position of the I/P dimmer switch, thumbwheel. 

Light Sensor  

The scan tool displays the output voltage of the ambient light sensor based on the intensity of light 
detected. As the light intensity increases, the sensor displayed voltage decreases. In the LIGHT state, a 
low voltage, not less than 1.75 volts, is present and the DRL will be ON. In the DARK state, a high 

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Vehicle in PARK/Park brake RELEASED/Headlamps in AUTO/All 

doors/tailgate closed

Cargo Lamp On

Input/Output

On/Off

Off

Display Dimming

Input/Output

Percent

Varies

High Beam Lamp

Input/Output

On/Off

Off

Left Turn Input

Input/Output

Open/Closed

Open

Right Turn Input

Input/Output

Open/Closed

Open

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

voltage, up to 4.9 volts, is present and the headlamps will be ON.

Memory Switch Backlight  

The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM 
to the PWM controlled memory switch backlight based on the position of the I/P dimmer switch, 
thumbwheel. 

Window Switch Backlight  

The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM 
to the PWM controlled window switch backlight based on the position of the I/P dimmer switch, 
thumbwheel. 

Inputs 

Courtesy Lamp Relay  

The scan tool displays the State of the courtesy lamp relay. The scan tool displays ON when the switch is 
turned ON. The scan tool also displays On when the park lamp input indicates On. 

Courtesy Lamp Switch  

The scan tool displays the position of the courtesy lamp switch. The scan tool displays Active when the 
switch is turned ON. The BCM uses this data in controlling the operation of the courtesy lamps. 

Dimming Enable  

The scan tool displays if the dimming feature of the module is enabled or disabled. The scan tool displays 
On when the dimming feature of the module is enabled. 

Door Ajar Switch  

The scan tool displays Off when the drivers door is fully closed or On when the drivers door is open or 
ajar. 

DRL Disable Switch  

The scan tool displays the position of the daytime running lamp (DRL) disable switch. The scan tool 
displays Active when the DRL disable switch is pressed and Inactive when released. The BCM uses this 
data in controlling the operation of the automatic lamp control (ALC) and DRL. 

Flash to Pass Switch  

The scan tool displays the position of the flash to pass switch. The scan tool displays On when the switch 
is pulled to activate the high beams momentarily while the switch is held.

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2