Hummer H2. Manual - part 486

z

The rear door lock switch  

z

The door lock relay  

z

The door unlock relay  

z

The liftgate lock relay-utility vehicles with liftgate only  

z

The reversible door lock actuators in each of the doors and liftgate  

z

LOCKS 20A fuse (rear lock/unlock relay supply voltage)  

z

ECC 10A fuse (liftgate lock relay supply voltage)  

Door Lock System Controls 

The power door lock system can be controlled by any of the following: 

z

A power door lock or unlock switch activation  

z

A keyless entry transmission  

z

An automatic door lock function  

z

A delay lock function  

z

Door lock cylinder switch activation  

z

Lockout Prevention  

z

An airbag deployment  

Driver, Passenger and Cargo Door Lock System Operation 

The front power door lock switches are integral components of the driver door module (DDM) and passenger 
door module (PDM). The switches are two position normally open rocker switches. When placed in either the 
lock or unlock positions, the switches provide a direct input to the DDM or PDM. The DDM or PDM monitors 
these inputs and sends a Class 2 message indicating a change in the switch's respective position. Modules which 
activate the power door lock motors receive the Class 2 message and activate the motor in the appropriate 
direction to lock or unlock the vehicle's doors and liftgate. The rear door lock switch provides a lock and unlock 
signal to the body control module (BCM). The BCM upon receipt of a lock or unlock signal will control the rear 
door lock relays and also send a Class 2 message to the DDM and PDM to perform the appropriate function. 

The modules which activate the power lock motors are: 

z

The DDM (driver door lock actuator).  

z

The PDM (passenger front door lock actuator).  

z

The BCM (both rear door lock actuators and cargo door/liftgate).  

The DDM and PDM are directly connected to the respective door lock actuator through the door lock motor 
lock and unlock circuits. Once a door lock or unlock request has been received, the module will supply battery 
voltage to one side of the actuator and ground the other causing the doors to lock or unlock. 

The rear passenger and cargo doors differ slightly in that they use lock and unlock relays. The relays supply and 
coil sides receive a constant voltage through the battery voltage supply circuit. The normally closed contacts are 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

  

connected to ground and the control side is connected to the BCM. Once a door lock or unlock request has been 
received by the BCM, the BCM will ground the control side of the appropriate relay. This energizes the relay 
and allows voltage to be applied to either the door lock motor lock or unlock circuits. since the other side of the 
door lock actuator is connected to the normally closed contacts of the opposing relay to ground, the doors lock 
or unlock. 

Liftgate Locking Operation 

The liftgate will lock any time the vehicle is shifted out of park on vehicles equipped with an automatic 
transmission and at vehicle speeds exceeding 5 kph with manual transmission. This happens in conjunction with 
auto door locks if enabled or independently of auto door locks if the feature is disabled. This ensures that the 
liftgate is locked anytime the vehicle is shifted out of park or when the vehicle is in motion. 

The liftgate lock relay supply and coil sides receive a constant voltage through the battery voltage supply circuit 
and the ECC fuse. The normally closed contact is connected to ground and the control side is connected to the 
body control module (BCM). A lock function will occur when a door lock switch activation, keyless entry lock 
transmission, auto door lock function or a liftgate lock function has been received by the BCM. The BCM will 
then ground the control side of the liftgate lock relay. This energizes the relay and allows voltage to be applied 
to the liftgate lock actuator lock control circuit. Since the other side of the liftgate lock actuator is connected to 
the normally closed contacts of the door unlock relay to ground, the liftgate will lock. When an unlock function 
occurs the BCM will ground the control side of the unlock relay and the rear doors and liftgate will unlock. 

The BCM also runs diagnostics on the liftgate lock relay control circuit and will set DTC B3825 as current and 
also send a Class 2 message to the DIC. The DIC will display REPLACE LIFTGATE FUSE to inform the 
driver that a fault has been detected in the liftgate lock circuit and that the liftgate is not locked. Faults that will 
set the DTC and cause the DIC to display the message could be any of the following: 

z

An open ECC fuse  

z

An open or short to ground in the liftgate lock relay battery positive voltage circuit  

z

A faulty liftgate lock relay  

z

An open or short to ground in the liftgate lock relay control circuit  

z

A short to ground in the liftgate lock actuator lock control circuit  

z

A faulty BCM  

Programmable Automatic Door Locks 

The automatic door lock feature can be programmed to control the door lock system. The automatic door lock 
feature is factory programmed to have all doors lock and unlock. For detailed instructions on programming the 
automatic door locks, refer to Vehicle Personalization in Personalization. 

When the automatic door lock feature is programmed to control the door lock system, the driver door module 
(DDM), passenger door module (PDM) and body control module (BCM) will lock the vehicle doors if the 
following inputs are true: 

z

Ignition 1 input is active.  

z

All door jamb switch inputs are inactive. 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

  

z

Cargo door or liftgate/liftglass ajar inputs are inactive.  

z

Transmission is shifted out of park.  

This automatic door lock function will only occur once per ignition cycle unless, a door jamb switch input 
changes state to active and back to inactive. Then the DDM, PDM and BCM will lock all doors again. 

Once the automatic door lock feature has locked the doors, the BCM will then unlock all the doors when the 
transmission is shifted into park. 

Lockout Prevention 

This feature prevents the locking of the driver door if the ignition key is left in the ignition lock cylinder. If a 
lock function occurs from any door lock switch and the body control module (BCM) senses an active state on 
either the left front door latch signal, secondary door latch switch signal and/or the liftgate ajar switch signal 
circuits and the key in ignition switch signal circuit is in the YES state, the BCM, driver door module (DDM) 
and passenger door module (PDM) will lock the doors and then the DDM will unlock the driver door. 

Delayed Locking Operation 

With any door open and a door lock switch is activated in the lock position, the driver door module (DDM), 
passenger door module (PDM) and the body control module (BCM) will go into a lock pending state. The BCM 
will also give three audible chimes. When the door is closed, the DDM, PDM and the BCM will lock the doors 
after approximately five seconds. This feature can be overridden by activating the door lock switch a second 
time and the doors will lock even with a door open. 

Unlock After Air Bag Deployment 

This feature will unlock all of the vehicle doors 15 seconds after an air bag deployment. 

DOOR AJAR INDICATOR DESCRIPTION AND OPERATION 

Door Ajar Indicator System Components 

The door ajar indicator system consists of the following components: 

z

The driver door module (DDM)  

z

The passenger front door module (PDM)  

z

The body control module (BCM)  

z

The instrument panel cluster (IPC)  

z

The driver information center (DIC)  

z

The driver door ajar switch  

z

The passenger door ajar switch  

z

The left rear door ajar switch  

z

The right rear door ajar switch  

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

  

z

The liftgate ajar switch  

Driver Door Ajar And Passenger Door Ajar 

The DDM and PDM receive a discrete input from the respective door ajar switch to indicate the status of the 
door. The DDM or PDM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of 
this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 
message to the radio to activate the door ajar audible warning when the following conditions are met: 

z

The transmission is removed from PARK  

z

The vehicle speed is greater then 8.05 km/h (5 mph)  

Left Rear Door Ajar And Right Rear Door Ajar 

The BCM receives a discrete inputs from both the left and right rear door and liftgate ajar switches to indicate 
the status of the doors and liftgate. The BCM then communicates this status to the IPC via class 2 message. The 
IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also 
send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are 
met: 

z

The transmission is removed from PARK  

z

The vehicle speed is greater then 8.05 km/h (5 mph)  

OUTSIDE MIRROR DESCRIPTION AND OPERATION (POWER MIRRORS) 

Power Mirror System 

Power Mirror System Components 

The power mirror system consists of the following components: 

z

The driver door module - Class 2 module with integrated switches and requires programming when 
replaced  

z

The passenger door module - Class 2 module with integrated switches, requires programming when 
replaced and also contains the RFA receiver  

z

The power mirror direction switch - Integrated into DDM and is a 4 position momentary switch that 
provides a signal input to the DDM for up, down, left/extend and right/retract with a mirror switch 
activation  

z

The mirror select switch - Integrated into DDM and is a 3 position switch that allows the operator to 
select the left or right mirror and also a neutral/fold position  

z

The left outside power mirror - Contains both the vertical and horizontal mirror motors and is serviced as 
a complete mirror assembly  

z

The right outside power mirror - Contains both the vertical and horizontal mirror motors and is serviced 
as a complete mirror assembly  

z

The body control module - Class 2 module that requires programming when replaced, serves as the power 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2