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 B3445 00: Stop Lamp Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

I/P Dimmer Voltage Reference

B1395 03 and B3600 03

B1395 03, B2652 00, and B3600 03

B1395 07

--

Stop Lamp Switch Signal

B1395 03 and B3600 03

3

3

--

CHMSL Control

B3884 00

3

3

--

Stop Lamp Control

B3445 00

3

3

--

I/P Dimmer Switch Low Reference

--

1

--

--

I/P Dimmer Switch Ground

--

2

--

--

1. Dimmer Switch Malfunction

2. Interior Backlighting Malfunction

3. Stop Lamp Switch Malfunction

Circuit/System Description

When the brake pedal is applied, the brake pedal switch normally closed contact signal circuit voltage is interrupted to the body control module (BCM). The BCM then applies a voltage to the stop lamp supply voltage circuit to the stop lamps.

Conditions for Running the DTC

    • The ignition is ON.
    •  The stop lamps must be commanded ON.

Conditions for Setting the DTC

The BCM detects a short to ground in the stop lamp supply voltage circuit when the stop lamps are commanded ON.

Action Taken When the DTC Sets

The stop lamps do not illuminate.

Conditions for Clearing the DTC

    • The conditions for setting the DTC are no longer present.
    • A history DTC clears after 100 malfunction-free ignition cycles.
    • The BCM receives the clear code command from the scan tool.

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 stop lamp.
  2. Test for less than 5.0 ohms between the ground circuit terminal B and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the listed stop lamp control circuit terminal below and ground.
  5. • Turn Signal Lamp terminal A
    • Tail/Stop Lamp terminal C
    • Center High Mounted Stop Lamp terminal A
  6. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.
  7. If the test lamp is always ON, test the control circuit for a short to voltage. If all circuits test 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 all circuits test normal, replace the BCM.
  8. If all circuits test normal, test or replace the inoperative stop lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Tail/Turn Signal Lamp Replacement
    •  High Mount Stop Lamp Replacement
    •  Control Module References for BCM replacement, setup, and programming