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 B0527 00: Right Turn Signal Circuit Low

DTC B0528 00: Right Turn Signal Circuit High

DTC B0529 00: Right Turn Signal Circuit Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Left Turn Indicator Supply Voltage

B0525 00

1

1

--

Right Turn Indicator Supply Voltage

B0530 00

1

1

--

Turn Signal/Multifunction Switch Signal

2

2

2

--

Left Turn Signal Control

B0532 00

B0534 00

B0533 00

--

Right Turn Signal Control

B0527 00

B0529 00

B0528 00

--

Front Park/Turn Signal Lamps Ground

--

1

--

--

Rear Park/Turn Signal Lamp Ground

--

1

--

--

Turn Signal/Multifunction Switch Ground

--

2

--

--

  1. Turn Signal Malfunction
  2. Turn Signal Switch Malfunction

Circuit/System Description

Ground is applied at all times at G106 to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START position. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM then applies a pulsating voltage to the front and rear turn signal lamps through there respective voltage supply circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument panel cluster (IPC) requesting the respective turn signal indicator be pulsed ON and OFF.

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B0527

When the BCM receives a right turn signal command and the right front or rear turn lamp control circuit is shorted to ground.

B0528

When the BCM receives a right turn signal command and the right front or rear turn lamp control circuit is shorted to voltage.

B0529

When the BCM receives a right turn signal command and the right front or rear turn lamp control circuit is open.

Action Taken When the DTC Sets

The right front and/or right rear turn signals will not operate or will remain always on.

Conditions for Clearing the DTC

    • This DTC will clear on current status after the condition for setting the fault is corrected.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.

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 inoperative right turn signal lamp.
  2. Verify a test lamp illuminates between the ground circuit terminal G and B+.
  3. If the test lamp does not illuminate test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the control circuit terminal A and the ground circuit terminal G.
  5. Ignition ON, command the inoperative turn signal lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF.
  6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the inoperative lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Park/Turn Signal/Side Marker Lamp Bulb Replacement
    •  Tail Lamp Bulb Replacement
    •  Control Module References for BCM replacement, programming, and setup.