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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 533 (LIGHTING SYSTEMS)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B2552: BACKUP LAMPS CONTROL CIRCUIT LOWTEST DESCRIPTION
1999 GMC Forward Control 5.7 R, Automatic

Test Description

1999 GMC Forward Control 5.7 R, AutomaticSECTION Test Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 4:  Tests if ground is constantly being applied to the backup lamp relay.
DTC B2552

Step Action Yes No
Schematic Reference: Exterior Lights Schematics 
Connector End View Reference: Master Electrical Component List in Wiring Systems
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Lighting Systems 
2
IMPORTANT: This DTC may set under normal operating conditions. If the Backup Lamp System operates properly and there is no customer complaint related to the Backup Lamp System, do not continue with this diagnostic procedure.
  1. Block the drive wheels
  2. Press the brake pedal
  3. Place the gear selector in the REVERSE position and back to the PARK position.
Do the backup lamps operate as expected?		 Go to Diagnostic Aids Go to Step 3 
3 Is the TRN SIG fuse in the console fuse block open? Go to Step 7  Go to Step 4 
4 
  1. Disconnect the backup lamp relay.
  2. Connect a test lamp between the ignition voltage circuit, coil side and the backup control circuit of the backup lamp relay connector.
  3. With the brake pedal pressed, place the gear selector in the REVERSE and back to the PARK positions.
Does the test lamp illuminate as expected?		 Go to Step 5  Go to Step 6 
5 Inspect for poor connections at the harness connector of the backup 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 10  Go to Step 8 
6 Inspect for poor connections at the harness connector of the body control module (BCM). 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 10  Go to Step 9 
7 Repair a short to ground in the backup lamp supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 10  -
8 Replace the backup lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) in Wiring Systems.
Did you complete the replacement?		 Go to Step 10  -
9
IMPORTANT: Perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.
Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?		 Go to Step 10  -
10
  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.