GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Sierra Classic - 4WD 🢒 Body Systems 🢒 Mirrors 🢒 DTC B1544, B1600, or B1605

Circuit Description

The driver door and passenger door modules supply battery positive voltage and ground on opposing mirror motor control circuits upon receipt of a mirror switch activation or a class 2 message commanding mirror control, memory recall or mirror tilt in reverse functions.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B1544 Mirror Motors Common Circuit
    • DTC B1600 Mirror Motor Vertical Circuit
    • DTC B1605 Mirror Motor Horizontal Circuit

Conditions for Running the DTC
    • System voltage must be between 9-16 volts.
    • The mirror motor control circuits must be active.

Conditions for Setting the DTC
    • If the mirror motor control circuits are switched to battery voltage and the mirror motor control circuit is shorted to ground
    • If the mirror motor control circuits are switched to ground and the mirror motor control circuit is shorted to battery voltage

Action Taken When the DTC Sets

The outside rearview mirror will not operate properly on all axes.

Conditions for Clearing the DTC

When the fault is no longer present, the door module changes the current DTC to a history DTC. The door module will clear the history DTC after 50 fault-free ignition cycles, or in response to a scan tool command.

Step

Action

Yes

No

Schematic Reference: Outside Rearview Mirror Schematics

Connector End View Reference: Mirror Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn ON the ignition, with the engine OFF.
  2. Activate the mirror switch in the up, down left and right positions.

Does the mirror move properly with each activation?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Disconnect the mirror from the appropriate door module.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe each of the mirror motor down, right and up/left control circuit pins at the door module one at a time with a test lamp that is connected to a good ground.

Did the test lamp illuminate at any of the test points?

Go to Step 7

Go to Step 4

4
  1. Connect a test lamp between the mirror motor down control circuit pin and a good ground.
  2. Activate the mirror switch to the down position.

Does the test lamp illuminate?

Go to Step 5

Go to Step 8

5
  1. Connect a test lamp between the mirror motor right control circuit pin and a good ground.
  2. Activate the mirror switch to the right position.

Does the test lamp illuminate?

Go to Step 6

Go to Step 8

6
  1. Connect a test lamp between the mirror motor up/left control circuit pin and a good ground.
  2. Activate the mirror switch to the up and left positions.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

7

Inspect for poor connection at the harness connector of the appropriate door module. Refer to Testing for Intermittent Conditions and Poor Connections .

Did you find and correct the conditions?

Go to Step 10

Go to Step 9

8

Replace the appropriate door module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

9

Replace the mirror. Refer to Outside Rearview Mirror Replacement .

Did you complete the replacement?

Go to Step 10

--

10
  1. Use the scan tool in order to clear the DTCs .
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK