GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Impala 🢒 DTC 🢒 DTC B3272

Circuit Description

The door lock switches provide a direct ground input to the body control module (BCM) when one of the switches is activated to the unlock position, or an input path to ground through a 470 ohm resistor when one of the switches is activated to the lock position. These inputs are used by the BCM to control the output to the door lock actuators.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3272 Driver Door Lock or Unlock Switch Circuit Low

Conditions for Setting the DTC

The BCM detects a short to ground in the driver door lock switch unlock signal circuit for greater than 60 seconds.

Action Taken When the DTC Sets
    • The BCM stores DTC B3272 in memory.
    • The BCM disables all output operations associated with the input.

Conditions for Clearing the DTC
    • A current DTC B3272 is cleared when the BCM no longer detects a short to ground in the driver door lock switch unlock signal circuit for greater than 60 seconds.
    • A history DTC B3272 is cleared after 100 consecutive ignition cycles with the condition for setting the DTC is no longer present.
    • The DTC is cleared using a scan tool.

Diagnostic Aids
    • If the DTC B3272 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to ground in the driver door lock switch unlock signal circuit
       - A door lock switch intermittently shorted to ground
       - A door lock switch that was held in the lock or unlock position for greater than 60 seconds
       - The BCM intermittently shorted to ground internally

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests to determine if the short to ground in the driver door lock switch unlock signal circuit is present.

    2.

  2. This step tests to determine if the short to ground in the driver door lock switch unlock signal circuit is intermittent.

    3.

  3. This step tests to determine if the driver door lock switch is shorted to ground.

    4.

  4. This step tests to determine if the front passenger door lock switch is shorted to ground.

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Power Door Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Door Unlock Switch parameter in the body control module (BCM) data list.

Does the scan tool display Inactive?

Go to Step 3

Go to Step 4

3

  1. Activate a door lock switch.
  2. With a scan tool, observe the Door Unlock Switch parameter in the BCM data list.

Does the door unlock switch parameter change state?

Go to Diagnostic Aids

Go to Step 7

4

  1. Turn OFF the ignition.
  2. Disconnect the driver door lock switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Door Unlock Switch parameter in the BCM data list.

Does the scan tool display Inactive?

Go to Step 8

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Connect the driver door lock switch.
  3. Disconnect the front passenger door lock switch.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the Door Unlock Switch parameter in the BCM data list.

Does the scan tool display Inactive?

Go to Step 8

Go to Step 6

6

Test the door lock switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the inoperative door lock switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

10

Replace the inoperative door lock switch. Refer to Door Lock Switch Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  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