Circuit Description

How the Circuit Works

System Description
The operation of the power windows is controlled by the main switch in the power window master switch. When the main switch is in OFF, only the driver's power window can be opened or closed. With the main switch in ON, the front passenger's window can be opened or closed by the power window master switch or by the front passenger's power window switch. The driver's power window switch has an automatic down or up mode which is turned on by holding the switch down or up momentarily.

The power windows are driven by reversible motors. Each motor is protected by a built-in circuit breaker. If the power window switch is held on too long (with the window obstructed, or after the window is fully up or down), the circuit breaker opens the circuit. The circuit breaker will reset automatically as it cools.

Driver's Window
With the ignition switch in ON (II) or START (III), battery voltage is applied to the driver's power window switch through the power window control unit. When the driver's power window switch is moved to DOWN, battery voltage is applied to the driver's power window motor. The motor's ground path is back through the power window control unit to G501. The motor then drives the window down. When the driver's power window switch is moved to UP, battery voltage is applied in the opposite direction and the motor drives the window up.

Auto Down
With the ignition switch in ON (II) or START (III), battery voltage is applied to the driver's power window switch through the power window control unit. When the driver's power window switch is held down momentarily, battery voltage is applied through the power window control unit to the driver's power window motor. The power window control unit receives pulses at the pulser input while the motor is running. When the window is fully down, the motor stops, and the pulses are no longer generated by the pulser. The control unit senses the lack of pulses at the pulser input, and stops applying battery voltage to the driver's power window motor.

Auto Up
With the ignition switch in ON (II) or START (III), battery voltage is applied to the driver's power window switch through the power window control unit. When the driver's power window switch is held up momentarily, battery voltage is applied through the power window control unit to the driver's power window motor. The power window control unit receives pulses at the pulser input while the motor is running. When the window is fully up, the motor stops, and the pulses are no longer generated by the pulser. The control unit senses the lack of pulses at the pulser input and stops applying battery voltage to the driver's power window motor.

Front Passenger's Window
With the ignition switch in ON (II) or START (III), battery voltage is applied to the coil of the power window relay. The contacts of the power window relay then close, applying battery voltage to the front passenger's power window switch and the power window master switch. With the main switch in ON, the front passenger window can be operated from the front passenger's power window switch or from the power window master switch.

When the front passenger's power window switch is moved to DOWN, battery voltage is applied to the front passenger's power window motor. The motor's ground path is back through the contacts in the front passenger's power window switch and the power window master switch to G501. The window moves down as long as the switch is held in the DOWN position. If the switch is moved to UP, battery voltage is applied in the opposite direction to the front passenger's power window motor, and the window moves up as long as the switch is held in the UP position.

When the front passenger's power window switch in the power window master switch is moved to DOWN, battery voltage is applied through the front passenger's power window switch contacts to the front passenger's power window motor. The motor's ground path is back through the contacts in the front passenger's power window switch and the power window master switch to G501. The window moves down as long as the switch is held in the DOWN position. If the switch is moved to UP, battery voltage is applied in the opposite direction to the front passenger's power window motor, and the window moves up as long as the switch is held in the UP position.