GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B2662 05: Parking Lamps Switch Circuit Open or High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Headlamp Switch AUTO Signal

3

B3909 05

B3909 05

B1456 05

Park Lamp Switch Signal

2

B2662 05

B2662 05

--

License Lamp Control

B3883 00

B3883 00

1

--

Park Lamp - RF Control

B3867 00

B3867 00

1

--

Park Lamp - LF Control

B2585 00

B2585 00

1

--

Marker Lamp - LF Control

1

1

1

--

Marker Lamp - RF Control

1

1

1

--

Marker Lamp Rear Control

B3871 00

B3871 00

1

--

License Lamp Ground

--

1

--

--

Headlamp Switch Ground

--

2

--

--

Marker Lamp - LF Ground

--

1

--

--

Marker Lamp - RF Ground

--

1

--

--

Marker Lamp - LR Ground

--

1

--

--

Marker Lamp - RR Ground

--

1

--

--

Park Lamps - LF Ground

--

1

--

--

Park Lamps - RF Ground

--

1

--

--

Tail/Stop and Turn Signal Lamps - LR Ground

--

1

--

--

Tail/Stop and Turn Signal Lamps - RR Ground

--

1

--

--

1. Park, License, and/or Tail Lamps Malfunction

2. Park Lamp Switch Malfunction

2. Headlamps Malfunction

Circuit/System Description

The headlamp switch is supplied with voltage from the instrument panel cluster (IPC) by two signal circuits, the headlamp signal circuit and the park lamp signal circuit. When the headlamp switch is placed in the PARK position, the park lamp signal circuit is provided with ground through the switch contacts of the park lamp switch to a common headlamp switch ground back to the IPC. The IPC interprets the flow of voltage and responds by sending a serial data message to the underhood electrical center (UEC) and the rear electrical center (REC) requesting the front and rear park lamps be activated. The UEC and REC respond by applying voltage to there respective park, marker, and license lamp control circuits illuminating the park, marker and license lamps.

Curb Side Parking Lamps

Curb side parking lamps is a feature that allows the vehicles owner to activate either the left or right side parks lamps while the vehicle is parked and the ignition is off. Curb side parking lamps is a European mandate and all vehicles sold in the United States will be programmed with it. This feature is software driven and cannot be changed or reprogrammed to illuminate it. To activate the curb side parking lamps the following conditions must be met:

  1. Ignition OFF.
  2. Turn signal switch placed in either the RIGHT or LEFT position.

When these conditions are met, the front and rear parking lamps for only the side selected will remain illuminated until the turn signal switch is placed in the neutral position or the ignition switch is cycled ON then OFF. This feature is not safe guarded by the vehicles battery rundown protection and in the event that the curb side parking feature is left ON, total battery discharge will occur. Upon activating the curb side parking lamps, an audible warning of three chimes will notify the vehicles owner that the feature is active.

Conditions for Running the DTC

    • Battery voltage must be between 9-16 volts.
    • Park lamps ON.

Conditions for Setting the DTC

The DTC will set when the IPC detects a short to voltage or an open/high resistance in the park lamp switch signal circuit.

Actions Taken When the DTC Sets

When DTC B2662 00 is present, the park lamps switch signal circuit will be disabled.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 11.
  3. If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  4. Ignition ON, verify the scan tool Parking Light Status parameter is OFF.
  5. If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPC.
  6. Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Parking Light Status parameter is ON.
  7. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  8. If all circuits test normal, replace the headlamp switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Headlamp Switch Replacement
    •  Control Module References for IPC replacement, setup, and programming