Chevrolet Sonic Repair Manual: Rear Window Defogger Description and Operation
- Rear Window Defogger System Components
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The rear window defogger system consist of the following components:
- The HVAC control module
- The body control module (BCM)
- The rear defogger relay
- The rear window grid
- Driver outside rearview mirror
- Passenger outside rearview mirror
- 30A fuse
- Rear Window Defogger Operation
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The BCM supplies 12?€‰V signal to the rear window defogger switch signal circuit to the HVAC control module. When you depress the rear window defogger switch, the rear window defogger switch pulls the signal circuit low. The BCM interprets as a request for the rear window defogger system. The BCM enables the rear window defogger system by supplying voltage to the rear defogger relay coil. The relay coil supply voltage is also spliced off internally in the BCM to the supply voltage circuit of the rear window defogger indicator. The rear defogger relay is energized and the rear window defogger indicator is illuminated. With the relay energized, battery positive voltage is allowed from the relay switched input through the switch contacts and out the relay switched output to the rear window defogger grid.
When you start the engine and press the rear window defogger switch for the first time, the defogger cycle lasts for 15?€‰minutes. Further operation results in 7.5?€‰minute defogger cycles. The rear defogger feature will not time out if vehicle speed is above 80?€‰km/h (50?€‰mph). The defogger cycle resets to 15?€‰minutes when you cycle the ignition to the OFF position and then to the ON position.
- Heated Mirrors
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The heated mirrors are also controlled through the rear defogger relay. Whenever the rear window defogger is turned on battery voltage is supplied to the mirror heater elements through the left and right mirror heater element control circuits.
Rear Side Door Window Weatherstrip Replacement (Sedan)
Rear Side Door Window Weatherstrip Replacement
Callout
Component Name
Preliminary Procedures
The rear door side window weatherstrip ...
Remote Keyless Entry (RKE) System Operation
The RKE transmitter may work up to 60?€‰m (195?€‰ft) away from the vehicle.
Other conditions can affect the performance of the transmitter. See Remote Keyless
Entry (RKE) System.
R ...
Other materials:
Dolly Towing from the Front
The vehicle can be towed from the front using a dolly. To tow the vehicle using
a dolly, follow these steps:
1. Attach the dolly to the tow vehicle following the dolly manufacturer's instructions.
2. Drive the front wheels onto the dolly.
3. Put an automatic transmission in P (Park) or a ...
Tire Pressure Indicator Sensor Learn
Special Tools
EL-46079 Tire Pressure Monitor Diagnostic Tool
EL-50448 Tire Pressure Monitor Sensor Activation Tool
For equivalent regional tools, refer to Special Tools.
Learn Mode Description
The tire pressure monitor system uses the instrument cluster, body control
module ...
Hydraulic Valve Lash Adjuster Arm Replacement
Hydraulic Valve Lash Adjuster Arm Replacement
Callout
Component Name
Preliminary Procedures
Remove the intake camshaft. Refer to Intake Camshaft Replacement.
Remove the exhaust camshaft. Refer to Exhaust Camshaft Replaceme ...
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