System Operation
Glass, Frames and Mechanisms
System Operation
System Diagram - Rear Window Defrost
Network Message Chart - Rear Window Defrost
FCIM (Front Controls Interface Module) Module Network Input Messages
HVAC (Heating, Ventilation, and Air Conditioning) Module Network Input Messages
Rear Window Defrost
When the rear window defrost switch (integral to the FCIM (Front Controls Interface Module)) is pressed and the engine is running, the HVAC (Heating, Ventilation, and Air Conditioning) module activates the rear window defrost relay located in the BJB (Battery Junction Box). When the rear window defrost relay is active, the rear window defrost grid is energized.
If equipped, the rear window defrost can also be commanded on and off using voice commands or by touching the rear window defrost button located on the touchscreen interface (FDIM (Front Display Interface Module)). For additional information on voice or touchscreen commanded features, refer to the Owner's Literature.
The HVAC (Heating, Ventilation, and Air Conditioning) module deactivates the rear window defrost relay when one of these conditions is met:
- The rear window defrost switch is pressed when the feature is active.
- If equipped, the rear window defrost is commanded off using voice command or the touchscreen interface when the feature is active.
- Ignition state is changed from RUN to OFF.
- The 15-minute timer completes.
Delayed Accessory Power
The BCM (Body Control Module) controls voltage to the power windows, the audio system and the power roof opening panel (if equipped) with the accessory delay relay. The BCM (Body Control Module) activates the accessory delay relay whenever the ignition is in the RUN or the ACC position, or when the ignition is changed from RUN or ACC to the OFF position and the LH (Left Hand) and RH (Right Hand) front doors are closed.
The BCM (Body Control Module) deactivates the accessory delay relay when:
- the LH (Left Hand) or RH (Right Hand) front door is ajar and the ignition is in the OFF or key-out position.
- ten minutes have elapsed since the ignition was changed from ACC or RUN to the OFF position.
Front Power Windows - XLT or Limited
NOTE: A new LH (Left Hand) or RH (Right Hand) front window motor cannot operate in one-touch up mode, and the bounce-back feature is disabled prior to initialization. If the switch is actuated to the auto UP position and released, window movement stops when the up 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 Testing and Inspection.
The LH (Left Hand) and RH (Right Hand) front window motors operate with the ignition in the RUN or ACC positions, or when the accessory delay relay is active. The high current required to move the front windows are supplied through the B+ and motor ground input.
The window control switch(es) sends 2 separate signals to the window motor: up and down. When the window control switch is pressed to the first detent position, a 12-volt signal is sent to the window motor to request 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. During an auto up or auto down request, the window motor determines intended window direction by the signal first received. 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. The up and down contacts are floating within the window control switch when the switch is in the neutral position. The up and down feeds to the window motor are all low current.
When the LH (Left Hand) or RH (Right Hand) front window motor is operating in auto or manual mode and the window control switch is held in the opposite direction, the glass movement will pause for a half second, then change direction.
The LH (Left Hand) and RH (Right Hand) front window motors have a security override feature. If an obstacle has been detected in the window opening as the window glass is moving upward, the window motor automatically reverses direction and moves the glass toward the bounce-back position (in both manual up and one-touch up modes). Once the window motor stops the glass at its bounce-back position, and within 2 seconds the switch is released, then held in the auto UP position, the window motor moves the glass up with no bounce-back protection (security override). If the switch is released before the window glass reaches the fully CLOSED position, the window motor stops with bounce-back automatically enabled for the next window up movement. If the ignition is turned to OFF or START (without delayed accessory), the window motor stops. The only exception is when an obstacle is detected in the window opening while delayed accessory power is not present. In this case the window motor bounces back, then stops. Ice, contaminant buildup and environmentally induced tight spots in the front window seals are all possible conditions that can activate the bounce-back feature. If an obstruction occurs between 4 mm (0.15 in) and 200 mm (7.87 in) of window opening, the bounce-back position is 250 mm (9.84 in) of window opening. If an obstruction occurs at a position more than 200 mm (7.87 in) of window opening, the bounce-back position is 50 mm (1.96 in) below where the obstruction occurred.
Front Power Windows - Base
The LH (Left Hand) front power window is equipped with a one-touch down feature (controlled by the LH (Left Hand) window control switch integral electronics). This allows the LH (Left Hand) front power window to be completely lowered when the LH (Left Hand) window control switch is pressed to the second detent position and then released.
Passenger Windows Lock-Out
When the lock-out switch (part of the LH (Left Hand) front window control switch) is in the LOCK position, the rear passenger power windows only operate from the LH (Left Hand) front window control switch.
Remote Start - Rear Window Defrost Operation
The customer can select different climate control modes/preferences when the vehicle is started using the remote start feature. This can be accessed through the message center. For additional information on setting the remote start preferences, refer to the Owner's Literature. When the rear defrost is set to AUTO mode, the rear window defrost activates when the outside temperature is less than 0 C (32 F) and the vehicle is started using the remote start feature. No climate control adjustments are recognized during remote start operation. Once the ignition is cycled to the ON position, the climate control system returns to the previous settings (last ignition ON cycle) and adjustments can be made normally. If the previous setting was off, the climate control system turns off.