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:
Sunroof Housing Front Drain Hose Replacement
Sunroof Housing Front Drain Hose Replacement
Callout
Component Name
Preliminary Procedure
It is only necessary to lower the headliner. Only do those steps in the
headliner replacement procedure that will lower the headliner ...
Heating and Air Conditioning System Description and Operation
Engine Coolant
Engine coolant is the key element of the heating system. The engine thermostat
controls the normal engine operating coolant temperature. Coolant pumped out
of the engine enters the heater core through the inlet heater hose. The air
flowing through the HVAC module abs ...
Control Solenoid Valve and Transmission Control Module Assembly Inspection
Verify the conditions listed below do not exist. Carefully
inspect the control solenoid valve assembly connectors and pins (1, 2, 4, 6)
for the condition. Repair or replace as necessary.
Damage
Bent pins
Debris
Broken retaining tab
Contamination
Verify there is ...
0.0097