Chevrolet Silverado / GMC Sierra. Manual — part 2664

If the parameter does not cycle between the specified values, replace the DDS.

3. Verify the vehicle is equipped with RPO DL3/DR4.

If the vehicle is not equipped with RPO DL3/DR4, refer to Mirror Motor Circuit
Malfunction below.

4. Observe the scan tool Mirror Horizontal Position and Mirror Vertical Position parameters.

The reading should be between 0.2 volts and 4.8 volts and change as the mirror is moved,
left, right, up, and down.

If not within the specified range or the parameter does not change as the mirror is
moved, refer to Mirror Position Sensor Circuit Malfunction below.

5. Command the left and right outside mirror to move up, down, left and right using the mirror

directional switch. The mirrors should move in the commanded direction.

If either mirror does not move in all commanded directions, refer to Mirror Motor
Circuit Malfunction below.

Circuit/System Testing

Mirror Motor Circuit Malfunction

1. Ignition OFF, disconnect the harness connector X3 at the appropriate door switch.

2. Ignition ON, verify a test lamp does not illuminate between the following control circuit

terminals and ground:

Control circuit terminal 1

Control circuit terminal 2

Control circuit terminal 6

If the test lamp illuminates, test the appropriate control circuit for a short to voltage.

3. Ignition OFF, test for infinite resistance between the following control circuits and ground:

Control circuit terminal 1

Control circuit terminal 2

Control circuit terminal 6

If less the specified value, test the appropriate control circuit for a short to ground.

4. Test for 40-100 ohms of resistance between the control circuit terminal 1 and the control

circuit terminal 6.

If not within the specified range, test both control circuits for an open/high resistance.
If the circuits test normal, test or replace the rearview mirror motor.

5. Test for 40-100 ohms of resistance between the control circuit terminal 2 and the control

circuit terminal 6.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Mirrors - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

If not within the specified range, test both control circuits for an open/high resistance.
If the circuits test normal, test or replace the rearview mirror motor.

6. If all circuits test normal, replace the appropriate door switch.

Mirror Position Sensor Circuit Malfunction

1. Ignition OFF, disconnect the harness connector X7 at the appropriate door switch.

2. Ignition ON, verify a test lamp does not illuminate between the following circuit terminals

and ground:

5-volt reference circuit terminal 7

Signal circuit terminal 4

Signal circuit terminal 5

Low reference circuit terminal 10

If the test lamp illuminates, test the appropriate circuit for a short to voltage.

3. Ignition OFF, test for infinite resistance between the following circuits and ground:

5-volt reference circuit terminal 7

Signal circuit terminal 4

Signal circuit terminal 5

Low reference circuit terminal 10

If less than the specified value, test the appropriate circuit for a short to ground.

4. Test for 4K-7K ohms of resistance between the 5-volt reference circuit terminal 7 and the

low reference circuit terminal 10.

If not within the specified range, test the 5-volt reference circuit and the low reference
circuit for an open/high resistance. If the circuits test normal, test or replace the
rearview mirror motor.

5. Test for 1K-7K ohms of resistance between the 5-volt reference circuit terminal 7 and the

signal circuit terminal 4.

If not within the specified range, test the signal circuit for an open/high resistance. If
the circuits test normal, test or replace the rearview mirror motor.

6. Test for 1K-7K ohms of resistance between the 5-volt reference circuit terminal 7 and the

signal circuit terminal 5.

If not within the specified range, test the signal circuit for an open/high resistance. If
the circuits test normal, test or replace the rearview mirror motor.

7. If all circuits test normal, replace the appropriate door switch.

Repair Procedures

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Mirrors - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Outside Rearview Mirror Motor Replacement

Control Module References for DDS or PDS replacement, setup, and programming

REPAIR INSTRUCTIONS

POWER MIRROR SWITCH REPLACEMENT (WITH DL8 AND WITHOUT SLT)

Fig. 6: Power Mirror Switch (with DL8 and without SLT)
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Mirrors - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado