Chevrolet Silverado / GMC Sierra. Service manual — part 2481

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 Verification

Ignition ON, press the brake pedal. The stop lamps should illuminate.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the affected stop lamp.

2. Test for less than 1 ohm of resistance between the ground circuit terminal A and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the stop lamp control circuit terminal D and the ground circuit

terminal A.

4. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF

when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage.

If the test lamp is always OFF, test the control circuit for a short to ground or an
open/high resistance.

5. If all circuits test normal, test or replace the affected stop lamp.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Tail Lamp Bulb Replacement (GMC) or Tail Lamp Bulb Replacement (Chevrolet)

Control Module References for BCM replacement, setup, and programming

DTC B3600

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 Descriptors

DTC B3600 03

Voltage Below Threshold

DTC B3600 07

Voltage Above Threshold

Diagnostic Fault Information

Circuit/System Description

Voltage for the interior backlighting components is supplied from the body control module
(BCM). The BCM applies a voltage reference through the 12-volt reference circuit to the
headlamp and panel dimmer switch. When the dimming switch is placed in the desired position,
the dimmed voltage setting is applied from the headlamp and panel dimmer switch through the
instrument panel (I/P) lamp dimmer switch signal circuit to the BCM. The BCM then applies the
dimmed voltage to the lamp supply voltage circuits and they are dimmed to the correct level.

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Instrument Panel Lamp Dimmer
Switch Signal

B3600 03

B3600 03

B3600 07

B3600 03 or

B3600 07

Reference Voltage

B1395 03

and B3600

07

B1395 03 and

B3600 07

B1395 07

B1395 03,

B1395 07 and

B3600 03,

B3600 07

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

B3600 03

The BCM detects a voltage that is lower than 0.10 volt on the I/P lamp dimmer switch signal
circuit.

B3600 07

The BCM detects a voltage that is higher than 4.97 volts on the I/P lamp dimmer switch signal
circuit.

Action Taken When the DTC Sets

The I/P lamps are not illuminated.

Conditions for Clearing the DTC

The BCM clears this code from current when the fault is removed from the system.

Reference Information

Schematic Reference

Interior Lights Dimming Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, headlamp switch to HEAD, vary the interior lamp dimming switch from dim to full
bright. The I/P lamps should dim and then become full bright.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the headlamp switch.

2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and

B+.

If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 volts.

If greater than the specified range, test the signal circuit terminal 13 for a short to
voltage. If the circuit tests normal, replace the BCM.

4. Ignition ON, test for 12 volts between the I/P dimming voltage reference circuit terminal 15

and ground.

If less than the specified value, test the voltage reference circuit for a short to ground
or an open/high resistance. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire between the signal circuit terminal 13 and the voltage

reference circuit terminal 15. Verify the scan tool BCM Dimming Control Signal parameter
is greater than 2.6 volts.

If less than the specified range, test the signal circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the BCM.

6. If all circuits test normal, test or replace the headlamp switch.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Headlamp Switch Replacement (without RPO SLT) or Headlamp Switch
Replacement (with RPO SLT)

Control Module References for BCM replacement, setup, and programming

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado