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 B2595 00: Right Cornering Lamp Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Park Lamp Switch ON Signal

2

2

2

--

LT/POS/LP Relay Control

1

1

B2590 00

--

RT/POS/LP Relay Control

1

1

B2595 00

--

Park Lamp Relay Control

1

1

1

--

License Lamp Control

1

1

1

--

Park Lamp Control

1

1

1

--

License Lamp Ground

--

1

--

--

Park Lamp Relay 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

--

--

Turn Signal/Multifunction Switch Ground

--

2

--

--

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

2. Park Lamp Switch Malfunction

Circuit/System Description

Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP and RT/POS/LP relays located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at G200 at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the left and right park lamp relay control circuits. This energizes the left and right park lamp relay coils causing the relay switch contacts to close allowing battery voltage to flow through the LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.

Conditions for Running the DTC

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

Conditions for Setting the DTC

DTC B2595 00 will set when the BCM detects a short to voltage in the right cornering lamp relay control circuit.

Actions Taken When the DTC Sets

When DTC B2595 00 is present, the right cornering lamps will not operate.

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 RT/POS/LP relay.
  2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground.
  3. If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the RT/POS/LP relay.
  6. Verify a test lamp illuminates between the B+ circuit terminal 86 and ground.
  7. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  8. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
  9. Command the Right Cornering Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  10. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the RT/POS/LP relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Control Module References for BCM replacement, setup, and programming