GM Service Manual Online
For 1990-2009 cars only

A Permanent Magnet (PM) Motor operates each of the power windows. Each motor raises or lowers the glass when the voltage is supplied to the motor. The direction the motor turns depends on the polarity of the supply voltage. The window switches control the supply voltage polarity.

Each motor is protected by a built-in 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 closes only after voltage is removed from the motor.

LF Window Switch Operation

When the ignition switch is in the RUN position, battery voltage is applied to the left front window switch through the PWR WDO Circuit Breaker and CKT 141. Battery voltage is applied to the window regulator motor when either of the up switches in the left front window switch are operated. The window regulator motor is grounded through the down contact in the left front window switch and CKT 750. The motor runs to drive the window up. When either of the down switches in the left front window switch are operated, the battery voltage is applied to the window regulator motor in the opposite direction. The window regulator motor is grounded through the up contact in the left front window switch. The motor runs to drive the window down.

Express Down Feature

The window will travel to the fully down position if the DN position in the left front window switch is momentarily pressed down past the first detent. Press the left front window switch to the UP position in order to stop the window.

RF Window Switch Operation

The battery voltage is applied to the right front window switch from the PWR WDO Circuit Breaker CKT 141 when the ignition switch is in the RUN position. The battery voltage is applied to the right front window regulator motor through CKT 666 when the UP position in the right front window switch is pressed. The motor is grounded through CKT 667, the down contact in the right front window switch, CKT 167, and the down contact in the left front window switch, and CKT 750, ground G302. The motor runs to drive the window up. The battery voltage is applied to the right front window regulator motor in the opposite direction through CKT 667 when the DN position in the right front window switch is pressed. The motor is grounded through CKT 666, the up contact in the right front window switch, CKT 166, the up contact in the left front window switch, and CKT 750, ground G302. The motor runs to drive the window down.

Rear Quarter Window Switch Operation

The rear quarter windows switch is on the interior lamp and multi-function switch. This switch allows you to open and close the left and right rear quarter windows. The battery voltage is applied to the rear quarter window switch when the ignition switch is in the RUN position. Voltage is applied to the quarter window actuators (CKT 902) when the OPEN position is pressed. The quarter window actuators are grounded through the close contact (CKT 901) in the rear quarter window switch. The motor runs to drive the rear quarter windows open. Battery voltage is applied to the motor in the opposite direction when the CLOSE position is pressed. The window motor is grounded through the open contact (CKT 902) in the rear quarter window switch. This closes the rear quarter windows.