GM Service Manual Online
For 1990-2009 cars only

Refer to

Headlamps Control


Object Number: 505936  Size: FS
Lighting Systems Components
Headlights/Daytime Running Lights (DRL) Circuit Description
Headlights and Power Distribution
Handling ESD Sensitive Parts Notice
Power, Grounds and RAP Relay
Headlights and Power Distribution
Headlights and Power Distribution
Headlights and Power Distribution
G201 (1 of 2)
LH HTD ST/BCM, DR LK, PWR MIR and CLSTR/BCM Fuses, HEADLAMP and RETAINED ACCSRY PWR Relays, and RETAINED ACCSRY PWR Circuit Breaker

Circuit Description

The Body Control Module (BCM) monitors the signal circuit of the high beam indicator control for high beam activity. When the high beam headlamps are commanded on by the DRL relay or the headlamp dimmer switch the high beam indicator control circuit is pulled to ground. B+ is applied to the DRL relay and the LH high beam headlamp from the DRL/EXT fuse and the RH high beam headlamp receives B+ 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 signal circuit of the high beam indicator control. 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

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 number(s) below refer to the step number(s) 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

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems in Lighting Systems.

2

  1. Install a scan tool.
  2. Set the parking 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 Hi 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

Are the high beam headlamps on at all times?

Go to Step 4

Go to Step 7

4

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

Does the scan tool display inactive?

Go to Step 11

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Reconect 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 Hi beam On switch parameter in the body control module data list.

Does the scan tool display inactive?

Go to Step 8

Go to Step 6

6

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

Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test the the high beam indicator control circuit for an open. Refer to Circuit Testing in Wiring Systems and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Inspect for a poor conection at the harness connector C201. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in wiring systems.

Did you find and corect the condition?

Go to Step 13

Go to Step 12

9

Inspect the high beam indicator control circuit for a poor conection at the harness connectors of the Body Control Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in wiring systems.

Did you find and corect the condition?

Go to Step 13

Go to Step 10

10

Important: perform the set up procedure for the Body Control Module (BCM) .

Replace the Body Control Module. Refer to Body Control Module Replacement in Body Control Systems.

Did you complete the replacement?

Go to Step 13

--

11

Replace the DRL relay.

Did you complete the repair?

Go to Step 13

--

12

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

Did you complete the repair?

Go to Step 13

--

13

  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