Principles Of Operation

Glass, Frames and Mechanisms

Principles of Operation

Power Windows

NOTE: The window motor operates with the ignition switch in the RUN or ACCESSORY positions, or when the accessory delay relay is active.

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 delayed accessory 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 not operate.

Each door window motor is a 7-pin motor with integral electronics and must be initialized whenever a new window motor has been installed. Initialization is required to learn the full up position 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 the window regulator or glass run, the window motor must be de-initialized, and then initialized.

When the window control switch is activated to the first detent position, a low current 12-volt signal is sent to the window motor to request either an up or down operation. When auto up or auto down is requested (switch pressed to the second detent position), the window control switch provides a 12-volt signal on both the up and down line simultaneously. Since the switch travels through the first detent prior to the second, the motor is able to determine which direction is desired. If the window control switch is pressed too quickly to the second detent position (less than 5 milliseconds of time between first detent signal and second detent signal), the window motor will not be able to determine the intended direction request and will not operate until the window control switch is released and pressed again. When the window motor is operating in auto up or auto down mode, movement of the window can be stopped by pressing the switch to any position (up, down, auto up, auto down). The window control switch must be released before the window will move again.

The window motor uses feedback from 2 internal Hall-effect sensors coupled to the internal microprocessor to determine window glass position and operate the window motor. If the Hall-effect pulses are not being received by the microprocessor, the window motor will run for approximately one-half second and stop each time the switch is pressed. The motor contains software controlled thermal protection to protect the motor windings from overcurrent/overtemperature operation. Continued excessive operation of the motor will cause the software control to shut off power to the motor, causing a loss of function until the window motor cools.

A new 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 window control switch is released. If the window motor is removed from the window regulator drum housing, or if a new window motor is installed, it must be initialized. Refer to Window Motor Initialization Testing and Inspection.

The 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 window motor will soft stall into the upper and lower positions contributing to extended durability of the system. If the window does not seal completely in the full up position (very small gaps/non bounce-back events only), the window switch can be actuated to the up position and the window will be energized for a fraction of a second to fully seal and this new position will be learned.

Bounce-Back

The 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.

Rear Window Defrost

When the rear window defrost switch (integral to the Front Controls Interface Module (FCIM)) is pressed and the engine is running, the HVAC module will activate the rear window defrost relay located in the Battery Junction Box (BJB). When the rear window defrost relay is active, the rear window defrost grid will be energized.

The HVAC module will deactivate the heated grid 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)

Global Open/Close (if equipped)

The Smart Junction Box (SJB) sends a signal on the global open/close circuit, to both front and rear door window motors, to open or close the windows based on a signal received from the Remote Keyless Entry (RKE) transmitter. If the accessory delay relay is active, the global open feature will not operate.

Delayed Accessory Power

NOTE: Refer to Description and Operation, Intelligent Access with Push Button Start in Antitheft and Alarm Systems to review the procedures for achieving the various ignition states (ignition OFF, ignition in ACCESSORY, ignition ON, ignition START) on vehicles with this feature.

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

The SJB controls power to the power windows and the power 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 (grounded when activated, open circuit when deactivated)