Chevrolet Silverado / GMC Sierra. Manual — part 2660

Ignition ON, press the rear window defogger switch. The rear window defogger and both heated
mirrors should become warm.

Circuit/System Testing

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 supply voltage circuit

terminal 7 and ground.

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

3. Ignition OFF, test for infinite resistance between the supply voltage circuit terminal 7 and

ground.

If less than the specified value, test the supply voltage circuit for a short to ground. If
the circuit tests normal, test or replace the applicable rearview mirror face.

4. Test for 5-10 ohms of resistance between the supply voltage circuit terminal 7 and the low

reference circuit terminal 3.

If not within the specified range, test the supply voltage circuit and the low reference
circuit for an open/high resistance. If the circuits test normal, test or replace the
appropriate rearview mirror face.

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

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Outside Rearview Mirror Glass Replacement

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

DTC B1722

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B1722 01

Mirror Power Fold Circuit Short to Battery

2008 Chevrolet Silverado 1500

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

DTC B1722 02

Mirror Power Fold Circuit Short to Ground

DTC B1722 04

Mirror Power Fold Circuit Open

Diagnostic Fault Information

Circuit/System Description

The Driver Door Switch (DDS) and Passenger Door Switch (PDS) control the power folding or
power extending functions of the outside rearview mirrors. The folding mirror motors are
controlled by using bi-directional motor controls through the folding mirror motor retract control
circuit and the folding mirror motor extend control circuit.

Conditions for Running the DTC

Mirror folding is requested.

Conditions for Setting the DTC

An improper voltage level is seen on either the folding mirror motor retract control circuit or the
folding mirror motor extend control circuit.

Action Taken When the DTC Sets

Power folding mirror operations are suspended so long as the fault is present.

Conditions for Clearing the DTC

A current DTC will clear when the fault is no longer present.

A history DTC will clear after 40 malfunction-free ignition cycles.

Reference Information

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Folding Mirror Motor Retract
Control

B1722 02

B1722 04

B1722 01

-

Folding Mirror Motor Extend
Control

B1722 02

B1722 04

B1722 01

-

2008 Chevrolet Silverado 1500

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

Schematic Reference

Outside Rearview Mirror Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Outside Mirror Description and Operation (Heated Mirrors) or Outside Mirror
Description and Operation (Power Mirrors)

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool References

Control Module References For Scan Tool Information.

Circuit/System Verification

Ignition ON, using the folding mirror switch, the left and right rearview mirrors should extend
and retract as commanded.

Circuit/System Testing

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:

Control circuit terminal 1

Control circuit terminal 2

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:

Control circuit terminal 1

2008 Chevrolet Silverado 1500

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