Contents Wiring diagrams Section: Exterior Lights All sections

Lighting Systems: Overview Chevrolet Silverado 1500 HD

Exterior Lights 27 illustrations ~1321 words

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

3. This step determines if an ignition switch power mode condition exists. The specified procedure will determine which diagnostic path is to be followed.

4. This step determines if a Body Control Module (BCM) DTC based diagnostic path or a symptom based diagnostic path are to be followed.

5. The presence of DTCs which begin with U indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

6. This step displays stored system related DTCs to be diagnosed.

Scheme 153

Scheme 153: Test Description

Scheme 154

Scheme 154: Scan Tool Output Controls

Scheme 155

Scheme 155: Scan Tool Data List

Scheme 156

Scheme 156

Scheme 157

Scheme 157

The numbers below refer to the step numbers on the diagnostic table.

5. Tests for voltage at the LED dimming signal circuit.

6. Tests for a BCM output to the headlamp switch.

7. Determines if it is the headlamp on indicator circuit or the BCM.

8. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 158

Scheme 158: Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. This step test determines if the problem exists in the wiring or the BCM.

4. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 159

Scheme 159: Test Description

The numbers below refer to the step numbers on the diagnostic table.

2. Listen for an audible click when the front fog lamp relay operates. Depress the switch for both the ON and OFF states. Repeat as necessary.

3. Tests for voltage at the coil side of the front fog lamp relay.

4. Verifies that the body control module (BCM) is providing ground to the front fog lamp relay.

5. Tests if ground is constantly being applied to the front fog lamp relay.

6. Tests if there is opposing voltage present or an open in the front fog lamp relay control circuit.

12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 160

Scheme 160: Test Description

Scheme 161

Scheme 161

The numbers below refer to the step numbers on the diagnostic table.

2. Listen for an audible click when the rear fog lamp relay operates. Depress the switch for both the ON and OFF states. Repeat as necessary.

3. Tests for voltage at the coil side of the rear fog lamp relay.

4. Verifies that the body control module (BCM) is providing ground to the rear fog lamp relay.

5. Tests if ground is constantly being applied to the rear fog lamp relay.

6. Tests if there is opposing voltage present or an open in the rear fog lamp relay control circuit.

12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 162

Scheme 162: Test Description

Scheme 163

Scheme 163

The numbers below refer to the step numbers on the diagnostic table.

3. This step test determines if the problem exists in the wiring or the BCM.

4. This step test determines if the problem exists in the wiring or the BCM.

5. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 164

Scheme 164: Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. Tests for voltage at the voltage supply side of the headlamp low beam relay.

4. Verifies that the body control module (BCM) is providing ground to the headlamp low beam relay.

5. Tests if ground is constantly being applied to the headlamp low beam relay.

6. Tests if there is opposing voltage present or an open headlamp low beam relay control circuit.

12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 165

Scheme 165: Test Description

Scheme 166

Scheme 166

The numbers below refer to the step numbers on the diagnostic table.

2. Listen for an audible click when the high beam relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

3. Tests for voltage at the coil side of the high beam relay.

4. Verifies that the body control module (BCM) is providing ground to the high beam relay.

5. Tests if ground is constantly being applied to the high beam relay.

6. Tests if there is opposing voltage present or an open high beam relay control circuit.

12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 167

Scheme 167: Test Description

Scheme 168

Scheme 168

The numbers below refer to the step numbers on the diagnostic table.

2. Listen for an audible click when the park lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

3. Tests for voltage at the coil side of the park lamp relay.

4. Verifies that the body control module (BCM) is providing ground to the park lamp relay.

5. Tests if ground is constantly being applied to the park lamp relay.

6. Tests if there is opposing voltage present or an open park lamp relay control circuit.

12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 169

Scheme 169: Test Description

Scheme 170

Scheme 170

The numbers below refer to the step numbers on the diagnostic table.

2. Listen for an audible click when the DRL relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

3. Tests for voltage at the coil side of the DRL relay.

4. Verifies that the body control module (BCM) is providing ground to the DRL relay.

5. Tests if ground is constantly being applied to the DRL relay.

6. Tests if there is opposing voltage present or an open in the DRL relay control circuit.

12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 171

Scheme 171: Test Description

Scheme 172

Scheme 172

The numbers below refer to the step numbers on the diagnostic table.

2. This step test determines if the problem exists in the wiring or the BCM.

3. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 173

Scheme 173: Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. This step test determines if the problem exists in the wiring or the BCM.

4. This step test determines if the problem exists in the wiring or the BCM.

5. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 174

Scheme 174: Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. Tests for the proper operation of the circuit in the low voltage range.

4. Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

5. Tests for a short to voltage in the 5 volt reference circuit.

6. Tests for a high resistance or an open in the dimming return circuit.

Scheme 175

Scheme 175: Test Description

Scheme 176

Scheme 176

The numbers below refer to the step numbers on the diagnostic table.

2. This step test determines if the problem exists in the wiring or the BCM.

3. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 177

Scheme 177: Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. Tests for the proper operation of the circuit in the low voltage range.

4. Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

5. Tests for a short to voltage in the ambient light sensor low reference circuit.

13. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 178

Scheme 178: Test Description

Scheme 179

Scheme 179