Power Windows - Operation

OPERATION

POWER WINDOWS

A battery positive and negative connection to either of the two motor terminals will cause the motor to rotate in one direction. Reversing current through these same two connections will cause the motor to rotate in the opposite direction. Each motor is controlled by the Body Control Module (BCM).

The BCM controls the logic for the power windows. The BCM receives a muxed input from each window switch. The BCM uses the information to control the operation of the power windows if the ignition is in Run or Accessory (including delay).

An auto-down feature allows either window to be lowered all the way, even if the window switch is released. Each window has a switch that must be depressed in the down direction to a second detent to begin the auto-down function. Depressing the switch again in any direction will immediately stop the window.

Another feature is Smart Glass. The window glass is designed to slide up into a seal to prevent the windows from "popping" out at high speeds. To prevent the glass from hanging up on the seal, the BCM drops the glass when the door is opened, and returns it to the full up position once the door is closed.

SMART GLASS FEATURE

The Smart Glass feature of the power window system drops the window 10 mm when the doors are unlatched. This allows the window glass to clear the weather strip that the glass seals in.

The distance the windows drop is based on the learned "up stop" of the window. Each power window motor has a Hall effect switch that the Body Control Module (BCM) uses to monitor window movement. When the window stops moving while the switch is still being pressed, it memorizes this position as the "up stop" and calculates the window drop from this position. The Hall effect switch is also used by the BCM to shut off electrical current to each power window motor when it has stopped moving.