Windows: Description and Operation

CIRCUIT OPERATION
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 the motor turns depends on the polarity of the supply voltage.

The Master Switch Assembly controls all of the Power Window Motors and the Power Window Control Module. Each Window Switch controls only one of the Power Window Motors.

MASTER SWITCH ASSEMBLY OPERATION
When the Ignition Switch is in "RUN," battery voltage is applied to the Master Switch Assembly through the PWR WDO Circuit Breaker and CKT 76.

When any of the "UP" switches in the Master Switch Assembly not associated with Express Down are operated, battery voltage is applied to the Power Window Motor. The Power Window Motor is grounded through the "DN" contact in the Master Switch Assembly. The Power Window Motor runs to drive the window up. When any of the "DN" Switches in the Master Switch Assembly are operated, battery voltage is applied to the Power Window Motor in the opposite direction. The Power Window Motor is grounded through the "UP" contact in the Master Switch Assembly. The Power Window 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 be fully opened by holding the LH Front window Switch "DN" for more than 0.3 seconds then releasing it. If the LH Front Window Switch is held "DN" for less than 0.3 seconds, the window will only move down a small distance.

When the Ignition Switch is in "RUN" the Power Window Control Module receives power at term "A." When the LH Front Switch is held "DN" 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 Front "UP" Switch in the Master Switch Assembly to ground. The relay contacts close and the LH Front Power Window Motor receives battery voltage. The other terminal of the motor is grounded through the Master Switch Assembly LH front "UP" contact. When the window is fully down, the motor stall current will be detected at the current sense input of the Timer and Control Unit. The Relay Control switch will be opened, de-energizing the coil and disconnecting power to the motor. The motor will also be stopped 20 +/- 10 seconds after the LH Front "DN" Switch is pushed.

If the LH Front "UP" or "DN" Switch is pushed while operating in the Express Down mode, the Timer and Control Unit will detect this at the Up-Stop Input terminal and open the Relay Control switch. CK 164 at the other LH front power window terminal is now not grounded through the Master Switch Assembly. The window will stop moving down and will move up if the LH Front "UP" Switch is held. If the Power Input at term "A" of the Power Window Control Module is lost, the power window will still operate 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 the PWR WDO Circuit Breaker and CKT 76. When the "UP" Switch in a Window Switch is operated, battery voltage is applied to one terminal of the Power Window Motor. The other terminal is grounded through the "DN" contact in the Window Switch and the "DN" contact in the Master Switch Assembly. The Power Window Motor runs to drive the window up. When the "DN" Switch in the Window Switch is operated, battery voltage is applied to the Window Motor in the opposite direction. The Power Window Motor is grounded through the "UP" contact in the Window Switch and the "UP" contact in the Master Switch Assembly. The Power Window Motor runs to drive the window down.

Each motor is protected by a built-in electronic circuit breaker PTC. If a Window Switch is held too long with the window obstructed or after the window is fully up or down, the PTC resistance increases. The resistance returns to normal after voltage is removed from the motor terminals.