Circuit/System Description
The body control module (BCM) controls the rear window defog relay located in the underhood fuse block. The rear window defog switch located on the HVAC control module is hard wired to the BCM. The rear window defog switch provides the request signal to the BCM. With the ignition switch in the RUN position, the BCM supplies voltage to the rear window defog switch via the rear defog switch signal circuit. When the rear window defog switch is pressed, the switch contacts close and ground is supplied. The BCM interprets the flow of voltage as a request to turn the rear defogger ON. The BCM energizes the rear window defog relay by applying voltage to the relay coil via the rear defog relay control circuit. When the rear window defog relay coil is energized, the switch contacts of the rear window defog relay close allowing battery voltage to flow from the REAR DEFOG fuse through the closed switch contacts and out the relay switched output to the rear window defogger grid. Ground for the rear window defogger grid is provided at G301. The BCM also illuminates the rear defog indicator LED located on the HVAC control module with the supplied voltage from the rear defog relay control circuit.
The body control module (BCM) controls the rear window defog relay located in the underhood fuse block. The rear window defog switch located on the HVAC control module is hard wired to the BCM. The rear window defog switch provides the request signal to the BCM. With the ignition switch in the RUN position, the BCM supplies voltage to the rear window defog switch via the rear defog switch signal circuit. When the rear window defog switch is pressed, the switch contacts close and ground is supplied. The BCM interprets the flow of voltage as a request to turn the rear defogger ON. The BCM energizes the rear window defog relay by applying voltage to the relay coil via the rear defog relay control circuit. When the rear window defog relay coil is energized, the switch contacts of the rear window defog relay close allowing battery voltage to flow from the REAR DEFOG fuse through the closed switch contacts and out the relay switched output to the rear window defogger grid. Ground for the rear window defogger grid is provided at G301. The BCM also illuminates the rear defog indicator LED located on the HVAC control module with the supplied voltage from the rear defog relay control circuit.
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.
Adhesive Service Kit Description
The GM Adhesive Caulking Kit P/N 12346392 contains the following items
- 4 different primers
- A tube of urethane adhesive with a nozzle
- 4 daubers
- Instructions with warnings
- Use the urethane adhesive caulking kit for replacement of any urethane adhesive-installed window using the Full Cut Method. You may use an equivalent urethane adhesive system if the system meets GM Specification GM 3651M. Always follow the system manufacturer's instructions for application, handling, and curing.
Stationary Window Description
Most stationary windows, specifically windshields, are retained to the body with urethane adhesive which adheres the window to the body. This increases structural integrity. The reinstallation of windows with urethane adhesive requires complete replacement of the urethane adhesive bead
The extended method (also known as long method, full strip or full cut) is the only recommended procedure for General Motor Vehicle.
Power Window Motor Operation
The driver and passenger power windows each contain a reversible power window motor. The direction the window travels is dependent upon the polarity of the supply voltage. By reversing the polarity of the supply voltage, the window motor is capable of moving the power window Up or Down. The power window motors are protected by an internal circuit breaker.
Power Window Operation
The power window system will operate when the ignition switch is in the ACC or RUN position. The power window system also operates whenever the body control module (BCM) is in the retained accessory power (RAP) mode. Battery voltage is supplied to the power window switches through the accessory voltage supply circuit. The passenger door window can be operated, either from a power window switch built into the driver door switch assembly (DDSA), or from a power window switch mounted locally on the passenger door. The driver door window can be operated only from the driver door power window switch built into the DDSA. Both driver and passenger power window switches receive a constant ground source.
The power window motor control circuits are connected to ground through the normally closed up and down 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 supplied with 12 volts that is applied to the down side of the power window motor. Ground is supplied through the closed contacts of the power window Up switch allowing the power window to travel 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.
Rear Window Defogger Operation
The body control module (BCM) controls the rear window defog relay located in the underhood fuse block. The rear window defog switch located on the HVAC control module is hard wired to the BCM. The rear window defog switch provides the request signal to the BCM. With the ignition switch in the RUN position, the BCM supplies voltage to the rear window defog switch via the rear defog switch signal circuit. When the rear window defog switch is pressed, the switch contacts close and ground is supplied. The BCM interprets the flow of voltage as a request to turn the rear defogger ON. The BCM energizes the rear window defog relay by applying voltage to the relay coil via the rear defog relay control circuit. When the rear window defog relay coil is energized, the switch contacts of the rear window defog relay close allowing battery voltage to flow from the REAR DEFOG fuse through the closed switch contacts and out the relay switched output to the rear window defogger grid. Ground for the rear window defogger grid is provided at G301. The BCM also illuminates the rear defog indicator LED located on the HVAC control module with the supplied voltage from the rear defog relay control circuit.
When you start the engine and depress the rear window defogger switch, the defogger cycle lasts for 15 minutes. Further operation will result in 7.5 minute defogger cycles. The rear window defogger cycle resets to 15 minutes when the ignition is cycled from OFF to ON.
The rear window defogger will not time out if vehicle speed is above 50 mph (80 km/h).