Windows: Description and Operation
CIRCUIT OPERATIONWhen the Ignition Switch is in RUN, the RAP Relays are turned on by the Body Computer Module (BCM). Battery voltage is applied through RAP Relay 1, Circuit Breaker 21, and the RED/WHT (76) wires to the LH and RH Door Switch Assemblies. If the Relay fails, the LH and RH Door Switch Assemblies are powered through the Ignition Switch.
A permanent magnet (PM) motor operates each of the Power Windows. Each Motor raises or lowers the glass when voltage is supplied to it. The direction in which the motor turns depends on the polarity of the supplied voltage. The Switches control the supply voltage polarity.
Each Motor is protected by a built-in Solid State circuit breaker. If a Window Switch is held too long with the Window obstructed or after the
Window is fully up or down, the circuit breaker opens the circuit. The circuit breaker resets automatically when voltage is removed from the motor.
The LH Door Switch Assembly controls both motors and both Express Down Window Modules. The RH Door Switch Assembly controls the RH Window Motor and the RH Express Down Window Module.
Express Dawn Window Operation
The Express Down Window function is a convenience feature that allows the LH and RH windows to be fully opened by holding the LH or RH window switch down for more than 0.3 seconds then releasing. If either window switch is held down less than 0.3 seconds the window will only move down a small distance.
When the ignition is in RUN or the RAP Circuit is energized the Express Down Window Module receives power at terminal A. When the LH Window Switch is held down for more than 0.3 seconds and released the Timer and Control Unit detects this at the down input terminal. The Relay Control Switch closes completing the coil circuit through the UP Switch. The relay contacts close and the LH Window Motor receives battery voltage. Terminal A of the motor is grounded through the LH Door Switch Assembly UP contact. When the motor is fully down the motor stall current is detected at the current sense input of the Timer and Control Unit. The Relay Control Switch is opened, deenergizing the coil and disconnecting power to the motor. The motor will also be stopped 20 +/- 10 seconds after the DN switch is pushed.
If the LH UP or DN switch for the LH window is pushed while the operating in the Express Down mode the Timer and Control Unit will detect this and open the Relay Control Switch. The B terminal of the motor is now grounded through LH Door Switch Assembly. The window will stop moving down and will move up if the UP switch is held. If the power input at terminal A of the Express Down Module is lost the Power Window will still operate but without the Express Down feature.
The RH Window operates in similar fashion from the LH Door Switch Assembly. The RH Window can also be operated from the RH Door Switch Assembly which is connected in series with the LH Door Switch Assembly.