GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) controls the operation of the seat belt indicator. The seat belt indicator is located in the instrument panel cluster (IPC). The BCM turns the seat belt indicator ON by sending voltage through the seat belt indicator supply voltage circuit. The seat belt indicator receives ground through the seat belt indicator ground circuit.

The BCM turns the seat belt indicator ON for 55 seconds when the following conditions are met:

    • The ignition is ON.
    • The driver unbuckles the seat belt.

If the driver seat belt is fastened during the 55 second period, the BCM turns the seat belt indicator OFF. If the driver seat belt releases anytime during the same ignition cycle, the BCM turns the seat belt indicator ON again for 55 seconds.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 001 Seat Belt Indicator Supply Voltage Circuit Performance

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The BCM detects a short to voltage or a short to ground in the seat belt indicator supply voltage circuit.

Action Taken When the DTC Sets

    • The seat belt indicator does not turn on when the seat belt indicator supply voltage circuit shorts to ground.
    • The seat belt indicator stays on at all times when the seat belt indicator supply voltage circuit shorts to voltage.

Conditions for Clearing the DTC

A short to voltage or a short to ground in the seat belt indicator supply voltage circuit is no longer present.

Diagnostic Aids

    • Inspect for a short to voltage or a short to ground in the seat belt indicator supply voltage circuit.
    • Inspect for an internal short to voltage or a short to ground within the IPC.

Test Description

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

  1. This step tests to see if there is a short to voltage in the seat belt indicator supply voltage circuit

  2. This step tests to see if there is an open, high resistance, or a short to ground in the seat belt indicator supply voltage circuit

Step

Action

Yes

No

Schematic Reference: Seat Belt Schematics

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. Note the seat belt indicator while turning the ignition ON.
  2. Turn ON the ignition, with the engine OFF.

Does the seat belt indicator stay ON continuously?

Go to Step 3

Go to Step 7

3

  1. Turn OFF the ignition.
  2. Disconnect the body control module (BCM) connector C2. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  3. Turn ON the ignition, with the engine OFF.

Does the seat belt indicator stay ON continuously?

Go to Step 5

Go to Step 4

4

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 8

--

5

  1. Disconnect the instrument panel cluster (IPC) connector C1. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  2. Test the seat belt indicator supply voltage circuit for a short to voltage.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

6

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

Did you complete the replacement?

Go to Step 8

--

7

  1. Disconnect the BCM connector C2. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  2. Disconnect the IPC connector C1. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  3. Test the seat belt indicator supply voltage circuit for an open, high resistance, or a short to ground.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

8

  1. Reconnect all components.
  2. Use the scan tool in order to clear the DTCs.
  3. 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