Power Windows Inoperative - Express Down Function

POWER WINDOWS INOPERATIVE - EXPRESS DOWN FUNCTION




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
Battery voltage is applied at all times to the coil and switch terminals of the ACCESSORY relay located in the body control module (BCM). When the ignition is placed in the RUN or ACCESSORY positions, or if retained accessory power (RAP) is active, the BCM grounds the accessory relay coil. This energizes the accessory relay, closing the switch side contacts and provides battery voltage to the WINDOWS fuse through to the driver and passenger power window switches. The power window motor control circuits are connected to ground through the normally closed up and down switch contacts of the power window switches. When a power window switch is placed in the down position, the power window motor down control circuit is switched to 12 volts. The power window motor up control circuit serves as ground and the window travels down. By placing the power window switch in the up position, the polarity of the power window motor is reversed and the window travels up.

CIRCUIT/SYSTEM TESTING
Power window inoperative in the express down function is the result of an internal circuit failure of the driver power window switch.
- Replace the driver power window switch.

REPAIR INSTRUCTION

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Power Window Switch Replacement