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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN PASSENGER EXTENDED, 5.0 MREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 919 (LIGHTING SYSTEMS)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B2585TEST DESCRIPTION
2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 M

Test Description

2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 MSECTION Test Description
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2001 GMC Yukon XL, 2001 GMC Yukon, 2001 GMC Sierra, 2001 GMC Cab & Chassis Sierra, and 2001 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The number(s) below refer to the step number(s) on the diagnostic table.

  1. 2 

    Command both the ON and OFF states. Repeat the commands as necessary.

  2. 3 

    This step determines if the condition is located in the interior lamps supply voltage circuit.

  3. 4 

    This step determines if the condition is located on the coil side or the switch side of the circuit.

  4. 6 

    This step determines if the body control module (BCM) is providing ground for the park lamp relay.

  5. 7 

    This step determines if a ground is constantly being applied to the park lamp relay.

  6. 25 

    After you replace the BCM, you must calibrate the new module for proper operation.

DTC B2585

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 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the park lamps relay ON and OFF.
Do the park lamps turn ON and OFF with each command?		 Go to Step 4  Go to Step 3 
3 
  1. Place the instrument panel dimmer switch in the full bright position.
  2. With a scan tool, command the park lamp relay ON and OFF.
Do the instrument panel lamps illuminate?		 Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 19 
4  With a scan tool, command the park lamp relay ON and OFF.
Do you hear a click when you command the park lamp relay ON and OFF?		 Go to Step 10  Go to Step 5 
5
  1. Turn OFF the ignition.
  2. Disconnect the park lamp relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the park lamp relay, coil side and a good ground.
Does the test lamp illuminate?		 Go to Step 6  Go to Step 21 
6 
  1. Connect a test lamp between the park lamp relay control circuit of the park lamp relay and the battery positive voltage circuit of the park lamp relay, coil side.
  2. With a scan tool, command the park lamp relay ON and OFF .
Does the test lamp turn ON and OFF with each command?		 Go to Step 17  Go to Step 7 
7  Does the test lamp remain illuminated with each command? Go to Step 9  Go to Step 8 
8 Test the park lamp relay control circuit of the park lamp relay for a short to voltage or an open. Refer to Circuit Testing , and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 26  Go to Step 18 
9 Test the park lamp relay control circuit of the park lamp relay 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 26  Go to Step 25 
10 Turn ON the ignition, with the engine OFF.
Do the park lamps operate continuously?		 Go to Step 11  Go to Step 12 
11
  1. Turn OFF the ignition.
  2. Disconnect the park lamp relay.
  3. Turn ON the ignition, with the engine OFF.
Do the park lamps operate continuously?		 Go to Step 20  Go to Step 24 
12
  1. Turn OFF the ignition.
  2. Disconnect the park lamp relay.
  3. Connect a test lamp between the battery positive voltage circuit of the park lamp relay switch and a good ground.
Does the test lamp illuminate?		 Go to Step 13  Go to Step 22 
13 Connect a 3 amp fused jumper wire between the battery positive voltage circuit of the park lamp relay switch and the interior park lamps supply voltage circuit of the park lamps.
Do the park lamps operate?		 Go to Step 17  Go to Step 14 
14 Test the interior park lamp supply voltage circuit of the park lamps for a high resistance or an open. Refer to Circuit Testing , and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 26  Go to Step 15 
15 Test the ground circuit of the park lamps for a high resistance or an open. Refer to Circuit Testing , and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 26  Go to Step 16 
16 Inspect for poor connections at the headlamp panel dimmer 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 26  Go to Step 23 
17 Inspect for poor connections at the park lamp relay. 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 26  Go to Step 24 
18 Inspect for poor connections at the harness connector of the body control module. 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 26  Go to Step 25 
19 Repair the high resistance, open or short to ground in the interior park lamps supply voltage circuit of the park lamps. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 26  -
20 Repair the short to voltage in the interior park lamp supply voltage circuit of the park lamps. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 26  -
21 Repair the battery positive voltage circuit of the park lamp relay coil. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 26  -
22 Repair the battery positive voltage circuit of the park lamp relay switch. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 26  -
23 Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement .
Did you complete the replacement?		 Go to Step 26  -
24 Replace the park lamp relay.
Did you complete the replacement?		 Go to Step 26  -
25 
IMPORTANT:

Perform the setup procedure for the body control module.

Replace the body control module. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?		 Go to Step 26  -
26
  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
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.