GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) monitors the high beam signal circuit for high beam activity. When the high beam headlamps are commanded on by the DRL relay or the headlamp dimmer switch the high beam signal circuit is pulled to ground. battery positive voltage is applied to the DRL relay and the LH high beam headlamp from the DRL/EXT fuse and the RH high beam headlamp receives battery positive voltage from the EXT fuse.

Conditions for Running the DTC

The headlamps are not on and the DRL is not enabled.

Conditions for Setting the DTC

    • The BCM detects a short to ground or open in the high beam signal circuit . When the headlamps are off and the DRL are off.
    • The condition above must be present for more than 0.3 seconds.

Action Taken When the DTC Sets

The BCM stores DTC B2582 in memory.

Conditions for Clearing the DTC

    • A current DTC B2582 will clear when the BCM no longer detects a short to ground or an open in the high beam signal circuit.
    • A history DTC B2582 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Diagnostic Aids

    • If the DTC B2582 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 signal circuit of the high beam indicator control.
       - An intermittent open in the signal circuit of the high beam indicator control.

Test Description

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

  1. Test the DRL relay for a stuck switch.

  2. Tests the headlamp dimmer switch for an internal short or bad switch.

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Install a scan tool.
  2. Set the park brake.
  3. Place a bright light over the ambient light sensor.
  4. Turn the headlamp switch to the OFF position.
  5. Turn ON the ignition, with the engine OFF.
  6. With a scan tool, observe the high beam ON switch parameter in the body control module input data list.

Does the scan tool display inactive?

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the DRL relay.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool observe the high beam ON switch parameter in the body control module data list.

Does the scan tool display inactive?

Go to Step 9

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Reconnect the DRL relay.
  3. Disconnect the headlamp dimmer switch at connector C201.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool observe the high beam ON switch parameter in the body control module data list.

Does the scan tool display inactive?

Go to Step 6

Go to Step 5

5

Test the high beam signal circuit for a short to ground. Refer to Circuit Testing in Wiring Systems and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for a poor connection at the harness connector C201. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

7

Inspect the high beam signal circuit for a poor connection at the harness connectors of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

8

Important: perform the set up procedure for the body control module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

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

Did you complete the replacement?

Go to Step 11

--

9

Replace the DRL relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

10

Replace the headlamp dimmer switch. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column.

Did you complete the repair?

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