Windows: Description and Operation

A permanent magnet (PM) motor operates each power window, raising or lowering the glass when voltage is supplied to it. The motor direction depends on the supply voltage polarity.

The Master Switch Assembly controls all the motors and the Express Down Window Module, while each individual window switch controls only one motor.

Master Switch Assembly Operation

When the Ignition Switch is in RUN, or when the BCM energizes the Retained Accessory Power Relay No. 1, battery voltage is applied to the Master Switch Assembly through Circuit Breaker 23.

When any Master Switch Assembly UP switch, not associated with Express Down, is operated, battery voltage is applied to the window motor. The window motor is grounded through the DN contact in the Master Switch Assembly and the motor runs to drive the window up.

When any Master Switch Assembly DN Switch is operated, battery voltage is applied to the window motor (reversed polarity from UP switch). The window motor is grounded through the UP contact in the Master Switch Assembly and the motor runs to drive the window down.

Express Down Window Operation

The Express Down Window function is a convenience feature that allows the LH front window to fully open by holding the LH Front Window Switch DN for more than 0.3 seconds and then releasing the switch. If the LH Front Window Switch is held DN for less than 0.3 seconds the window stops when the switch is released.

When the Ignition Switch is in RUN (or RAP circuit energized) the Express Down Window Module receives battery voltage at terminal A. When the LH Front 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 LH UP switch in the Master Switch Assembly to ground G200. The relay contacts close and the LH Window Motor receives battery voltage. Terminal B of the motor is grounded through the Master Switch Assembly LH UP contact. When the window is fully down the motor stall current is detected at the current sense input of the Timer and Control Unit. The Relay Control Switch opens, de-energizing the coil and disconnecting power to the motor. If the window is not fully opened 10-30 seconds after DN switch is pushed, the timer control de-energizes the coil, disconnecting power from the motor.

If the LH Front Window UP or DN Switch is pushed momentarily while operating in the Express Down mode, the window stops moving, and the Timer and Control Unit detects this at the UP input terminal and opens the Relay Control Switch. Now motor terminal B is not grounded through the Master Switch Assembly. The window stops moving down and moves up if the UP Switch is held. If the power input at the Express Down Module terminal A is lost, the power window still operates but without the Express Down feature.

Window Switch Operation

When the Ignition Switch is in RUN, battery voltage is applied to the window switches through Circuit Breaker 23, the closed contacts of the Window Lockout Relay, and the PNK (76) and PNK/WHT wires to terminal B. When the window switch UP switch is operated, battery voltage is applied to the window motor. The motor is grounded through the BRN (667, 669 or 671) wire, the Window Switch DN contact, and the Master Switch Assembly DN contact. The motor runs to drive the window up. When the window switch DN switch is operated, battery voltage is applied to the window motor in the opposite direction. The motor is grounded through the DK BLU (666, 668 or 670) wire, the window switch UP contact and the Master Switch Assembly UP contact. The motor runs to drive the window down. The Window Lockout Switch can disable the RH Front window switch and both rear window switches. When the Window Lockout Switch is closed, battery voltage energizes the Window Lockout Relay coil opening the normally closed relay contacts. This removes voltage from the PNK/WHT (1389) circuit and disables the window switches.

An electronic circuit breaker protects each motor. If a window switch is held too long while the window is obstructed, is fully up or fully down, the circuit breaker opens the circuit. The positive temperature coefficient (PTC) circuit breakers reset automatically when voltage is removed from the motors.