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Chevrolet Silverado / GMC Sierra. Manual - part 2771
Circuit/System Testing
Power Sunroof Malfunction
1. Disconnect the sunroof switch connector.
2. Verify that a test lamp illuminates between the ground circuit terminal 5 and B+.
If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, connect a 3A fused jumper wire between the signal circuit listed below and
ground. The sunroof should be inoperative in at least one or more directions.
Sunroof open terminal 6
Sunroof close terminal 4
Vent open (Crew Cab) terminal 2
Vent close (Crew Cab) terminal 8
If the sunroof moved in all directions, replace the sunroof switch.
4. Ignition OFF, disconnect the harness connector at the sunroof motor/actuator.
5. Verify that a test lamp illuminates between the ground circuit terminal 1 and B+.
If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
6. Verify that a test lamp illuminates between the B+ circuit terminal 6 and ground.
If the test lamp does not illuminate, test the B+ circuit for a short to ground or an
open/high resistance.
7. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 3 and
ground.
If the test lamp does not illuminate, test the ignition circuit for a short to ground or an
open/high resistance. If the circuit tests normal, refer to Power Mode Mismatch .
8. Ignition OFF, connect the sunroof motor/actuator harness connector.
9. Ignition ON, at the sunroof switch harness connector, test for 8.5-12.8 volts between the
signal circuits listed below and ground.
Sunroof open terminal 6
Sunroof close terminal 4
Vent open (Crew Cab) terminal 2
Vent close (Crew Cab) terminal 8
If less than the specified value, test the signal circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the sunroof motor/actuator.
10. If all circuits test normal, replace the sunroof motor/actuator.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Sunroof - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Crew Cab Power Sunroof Express Feature Malfunction
1. Ignition OFF, disconnect the harness connector at the sunroof switch.
2. Ignition ON, with the sunroof in the closed position, connect 3A fused jumper wires
between both signal circuits listed below and ground for less than 1 second. The sunroof
should express open.
Terminal 1
Terminal 6
If the sunroof did not express open, test the signal circuit terminal 1 for a short to
ground or an open/high resistance. If the circuit tests normal, replace the sunroof
motor/actuator.
3. With the sunroof in the open position, connect 3A fused jumper wires between both signal
circuits listed below and ground for less than 1 second. The sunroof should express open.
Terminal 1
Terminal 4
If the sunroof did not express open, test the signal circuit terminal 1 for a short to
ground or an open/high resistance. If the circuit tests normal, replace the sunroof
motor/actuator.
4. If all circuits test normal, replace the sunroof switch.
Component Testing
Sunroof Switch
1. Ignition OFF, disconnect the harness connector at the sunroof switch.
2. Test for infinite resistance between the switch terminals listed below and the ground circuit
terminal 5 with the switch in the open position.
Express open/close (Crew Cab) terminal 1
Sunroof close terminal 4
Sunroof open terminal 6
Vent close (Crew Cab) terminal 8
Vent open (Crew Cab) terminal 2
If not the specified value, replace the sunroof switch.
3. Test for less than 5 ohms between the switch terminals listed below and the ground circuit
terminal 5 with the switch in the closed position.
Express open/close (Crew Cab) terminal 1
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Sunroof - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Sunroof close terminal 4
Sunroof open terminal 6
Vent close (Crew Cab) terminal 8
Vent open (Crew Cab) terminal 2
If greater than the specified value, replace the sunroof switch.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Sunroof Motor/Actuator Replacement (Extended Cab) or Sunroof Motor/Actuator
Replacement (Crew Cab)
Sunroof Switch Replacement (Crew Cab)
REPAIR INSTRUCTIONS
SUNROOF AIR DEFLECTOR REPLACEMENT (EXTENDED CAB)
Removal Procedure
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Sunroof - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Fig. 2: Actuator Blocks
Courtesy of GENERAL MOTORS CORP.
1. Open the power sunroof window to the fully rear position.
2. Remove the actuators screws (1) and actuators (2) from each side of the sunroof module.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Sunroof - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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