GM Service Manual Online
For 1990-2009 cars only

Object Number: 331278  Size: MF
Body Control Module Components
Cell 114: Door Courtesy, IP Compartment, and Rear Compartment Lamps
Power Distribution Schematics
Power Distribution Schematics
Body Control System Connector End Views
Handling ESD Sensitive Parts Notice

Circuit Description

The body control module (PZM) may command the interior lamps through a discrete output to the courtesy lamps relay. The energized relay provides a ground for the interior lamps.

The PZM will test for a short to ground when Inadvertent power is active and the Interior lamps output is inactive and DTC B1971 is not current.

Conditions for Setting the DTC

The commanded state of the interior lamps does not match the feedback state.

Action Taken When the DTC Sets

The PZM continues to command the requested state until the instrument cluster revokes the request.

Conditions for Clearing the DTC

The commanded state matches the feedback state.

Step

Action

Value(s)

Yes

No

1

  1. Turn the ignition to the OFF position.
  2. Remove the courtesy relay.
  3. Connect a scan tool.
  4. Select BCM test, inadvertent power on the scan tool.
  5. Turn the inadvertent power ON.
  6. Measure voltage to ground from the courtesy relay terminal A9 (ORN).

Is battery voltage measured?

--

Go to Step 2

Go to Step 6

2

Measure the voltage from the courtesy relay terminal A9 (ORN) to terminal B7 (DK BLU)

Is battery voltage measured?

--

Go to Step 3

Go to Step 4

3

Replace the courtesy relay.

Is the relay replacement complete?

--

Go to Diagnostic System Check - Lighting Systems

--

4

Inspect CKT 1393 (DK BLU) for an open. Refer to Testing for Continuity in Wiring Systems.

Is CKT 1393 OK?

--

Go to Step 5

Go to Step 7

5

Replace the body control module. Refer to Body Control Module Replacement in Body Control System.

Is the body control module replacement complete?

--

Go to Diagnostic System Check - Lighting Systems

--

6

Repair the open or short to ground in CKT 640 (ORN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

7

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--