Principles Of Operation

Glass, Frames and Mechanisms

Principles of Operation

LH Front Power Window Operation

The LH front window motor contains integral electronics which must be initialized whenever a new window motor has been installed. Initialization is required to learn both the full UP and full DOWN positions and the profile of the glass as it travels through the glass channel. Once initialized, obstacle detection is enabled. When mechanical repairs have been carried out on either front window regulator or glass run, the LH front window motor must be de-initialized, and then initialized. The LH front window control switch sends 3 separate signals to the front window motor: up, down and auto. The front window control switch provides a 12-volt signal to the front window motor to request an up or down operation. When one-touch up or one-touch down is requested, the front window control switch provides a 12-volt signal on the up or down line and a ground signal on the auto line simultaneously. The up, down and auto feeds to the LH front window motor are all low current.

The LH front window motor operates with the ignition switch in the RUN or ACCESSORY positions, or when the accessory delay relay is active. The high current required to move the LH front window is supplied through a separate battery power circuit. For the motor to operate correctly, both power feeds and the ground feed must be intact at the window motor.

When the LH front window motor is operating in one-touch up or one-touch down mode, movement of the front window can be stopped by activating the switch in either direction. The front window control switch must be released before the window will move again.

Bounce-Back

The LH front window motor has a bounce-back feature. If an obstacle has been detected in the window opening as the window glass is moving upward, the window motor will automatically reverse direction and move the glass toward the bounce-back position (in both up and one-touch up modes). If an obstruction occurs between 4 mm (0.15 in) and 200 mm (7.87 in) of window opening, the bounce-back position will be 250 mm (9.84 in) of window opening. If an obstruction occurs at a position greater than 200 mm (7.87 in) of window opening, the bounce-back position will be 50 mm (1.96 in) below where the obstruction occurred.

Security Override

To override a bounce-back condition (to overcome the resistance of ice on the window or seals for example), within 2 seconds after the window reaches the bounce-back position, pull and hold the window control switch. The window will travel up with no bounce-back or pinch protection. If the window control switch is released before the window is fully closed, the window will stop. If the ignition switch is turned to OFF or START (without delayed accessory), the window motor will stop.

A new LH front window motor will not operate in one-touch up mode, and the bounce-back feature will be disabled prior to initialization. If the switch is actuated to the auto UP or auto DOWN position and released, window movement will stop when the up or down contact in the front window control switch is released. If the front window motor is removed from the window regulator drum housing, or if a new front window motor is installed, it must be initialized. Refer to Window Motor Initialization - Front Window Motor Initialization - Front.

The LH front window motor will automatically adjust to system changes throughout its life: changes in seal drag and slight changes in the full OPEN position will occur and will be automatically compensated for. Once initialized, the front window motors will soft stall into the upper and lower positions contributing to extended durability of the system. If the front window does not seal completely in the full UP position (very small gaps/non bounce-back events only), the front window switch can be actuated to the UP position and the front window will be energized for a fraction of a second to fully seal and this new position will be learned.

Passenger Window Operation

Passenger windows may be raised or lowered using the LH front window control switch or the corresponding passenger window control switch. Passenger window control switches receive power when the accessory delay relay is active and the LH front window lock switch is in the UNLOCK position. When the LH front window lock switch is in the LOCK position, the passenger windows will only operate from the LH front window control switch.

Rear Window Defrost

The rear window defrost relay is located in the Smart Junction Box (SJB). The rear window defrost switch is integral to the HVAC module (if equipped) or the manual climate control assembly.

For vehicles equipped with a HVAC module, when the rear window defrost switch is pressed to the ON position, the HVAC module sends a message through the Controller Area Network (CAN) to the SJB. When the SJB receives the rear window defrost ON message, the SJB starts a 10-minute timing function, and grounds the rear window defrost relay coil control circuit, which is hardwired to the SJB. When the rear window defrost relay is active, both the rear window defrost grid and heated mirror elements will be energized.

For vehicles equipped with a manual climate control assembly, when the rear window defrost switch is pressed to the ON position, the manual climate control assembly sends a ground signal to the SJB. When the SJB receives the rear window defrost request, the SJB will activate the rear window defrost relay. When the rear window defrost relay is active, both the rear window defrost grid and heated mirror elements will be energized.

The HVAC module/manual climate control assembly/SJB will deactivate the rear window defrost relay when one of the following conditions is met
- The rear window defrost switch is pressed when the feature is active
- Ignition switch state is changed from RUN to OFF/LOCK
- The 10 minute timing function is completed

Feature inputs
- Ignition switch RUN position (12V on both RUN and RUN/ACC inputs)
- Rear window defrost switch (momentary contact to ground when switch is pressed)

Feature outputs
- Rear window defrost relay control (grounded when activated, open circuit when deactivated)

Delayed Accessory Power

NOTE: The SJB may also be identified as the Generic Electronic Module (GEM).

The SJB controls power to the power windows and the roof opening panel (if equipped) with the accessory delay relay. Refer to the Wiring Diagrams for additional vehicle features powered by the accessory delay relay. The SJB activates the accessory delay relay whenever the ignition switch is in the RUN or the ACCESSORY position, or when the ignition switch is changed from RUN or ACCESSORY to the OFF/LOCK position and the LH and RH front doors are closed. Diagrams By Number

The SJB will deactivate the accessory delay feature when:

- the LF door is ajar and the ignition switch is in the OFF/LOCK or KEY-OUT position.
- the RF door is ajar and the ignition switch is in the OFF/LOCK or KEY-OUT position.
- ten minutes have elapsed since the ignition switch was changed from ACC or RUN to the OFF/LOCK position.

Feature inputs
- LF door ajar switch (open circuit with door closed, grounded with door ajar)
- RF door ajar switch (open circuit with door closed, grounded with door ajar)
- Ignition switch RUN position (battery potential on both the RUN and RUN/ACC inputs)
- Ignition switch ACC position (battery potential on the RUN/ACC input)
- Ignition switch OFF/LOCK position (absence of battery potential on the RUN, RUN/ACC and START inputs)

Feature outputs
- Accessory delay relay (control circuit grounded when activated, open circuit when deactivated)

Power Rear Window

NOTE: The power rear window motor does not communicate on the Controller Area Network (CAN).

The power rear window motor is an 8-pin motor with integral electronics. The power rear window control switch is located in the overhead console and provides a voltage signal to the motor to signal an open or close request. The integral electronics on the motor allow the power rear window to be moved to 3 positions: fully OPEN, fully CLOSED and VENT (approximately 50.8 mm [2 in] down from fully CLOSED).

When the power rear window is in the fully CLOSED position, pressing and releasing the control switch will lower the rear window to the VENT position. Pressing and releasing the control switch again will lower the rear window to the fully OPEN position. When the rear window is in the fully OPEN or VENT position, pulling and releasing the control switch will return the rear window to the fully CLOSED position.

The power rear window motor plastic pinion gear is mated to the drum housing of a single rail drum and cable window regulator. The motor is attached to the plastic drum housing by 3 screws. The motor uses internal Hall-effect sensor feedback coupled to the microprocessor to determine window position and operate the power rear window. If the microprocessor is not receiving the Hall-effect sensor pulses, the motor will run for approximately half a second, then enter error mode (window will become inoperative). The motor contains a thermal breaker to protect the motor windings from over-current/over-temperature operation. Continued successive operation of the motor will cause the thermal breaker to open, causing a loss of function until the power rear window motor cools. If this occurs, when the motor cools it will be in position recovery mode. Simply press the control switch momentarily and the power rear window will stall in the full OPEN position. Full functionality will then be restored.

The power rear window motor operates only with the ignition switch in the RUN/ACC position, or when the accessory delay relay is active. The motor is supplied with battery power and draws a key-off load of approximately 0.5 mA. All of the high current required to move the window is supplied through the battery and motor ground inputs. The loss of both logic and motor ground will cause this system to become inoperative. For correct functionality, both power feeds and one ground feed must be intact at the power rear window motor.

If an open or close command is selected while the ignition switch is in the RUN/ACC position, and the ignition switch is turned to OFF or START without accessory delay relay power enabled, the window will move to the fully OPEN or VENT position and stop.

Bounce-Back

If an obstacle is detected in the power rear window opening as the window is closing, the window will automatically reverse direction and move toward the fully OPEN position. This is known as bounce-back.

Security Override

To override a bounce-back condition (to overcome the resistance of ice on the window or seals for example), within 2 seconds after the window reaches the bounce-back position, pull and hold the window control switch. The window will travel up with no bounce-back or pinch protection. If the ignition switch is turned to OFF or START without accessory delay power enabled, the window will reverse direction with bounce-back re-enabled.

If the high current power circuit is disconnected from the power rear window motor while the window is in motion, the motor will enter position recovery mode when power is restored. Position recovery mode allows upward movement of the window in 15 mm (0.6 in) increments. If the control switch is pulled, the window will move in a one-touch down mode until it stalls in the fully OPEN position. If no internal or external faults exist, the motor will automatically resume normal operation.

The power rear window motor will suspend normal operation if a power rear window control switch error exists. A control switch error is defined as open and close energized at the same time. The window will be inoperative if a control switch error is present.

If the motor is removed from the window regulator drum housing, or if a new motor is installed, the window must be initialized. A new motor will be inoperative until initialized. Refer to Window Motor Initialization - Rear Window Motor Initialization - Rear.

The power rear window will automatically adjust to system changes throughout its life. Changes in seal drag and slight changes in the fully CLOSED position will occur and are automatically compensated for. Once initialized, the motor will soft stall into the lower position contributing to the extended durability of the system.