GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 TrailBlazer - 4WD 🢒 Body Systems 🢒 Mirrors 🢒 DTC B1724

Circuit Description

The door modules supply battery positive voltage and ground on opposing mirror motor control circuits based on the position of the mirror switch.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1724 Mirror Motor Control Circuit 2 Performance

Conditions for Running the DTC
    • System voltage must be between 9-16 volts.
    • The ignition switch must be in the ON position.

Conditions for Setting the DTC
    • If the mirror motor up/left control circuit is shorted to battery voltage and the mirror is commanded down or right
    • If the mirror motor up/left control circuit is shorted to ground and the mirror is commanded up or left

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: Vehicle Access 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 and left positions.

Does the mirror move up and left 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 the mirror motor up/left control circuit pin at the door module with a test lamp that is connected to a good ground.

Did the test lamp illuminate?

Go to Step 7

Go to Step 4

4
  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 position.

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5
  1. With the test lamp connected between the mirror motor up/left control circuit pin and a good ground.
  2. Activate the mirror switch to the left position.

Does the test lamp illuminate?

Go to Step 6

Go to Step 7

6

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

Did you find and correct the conditions?

Go to Step 9

Go to Step 8

7

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

Did you complete the replacement?

Go to Step 9

--

8

Replace the outside rearview mirror. Refer to Outside Rearview Mirror Motor Replacement .

Did you complete the replacement?

Go to Step 9

--

9
  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