Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- CHECK FOR AN ACTIVE DTC
- Turn the ignition on.
- Turn the Park Lamps on.
- With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Test complete. The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST
- CHECK THE (L3) LICENSE PLATE LAMP CONTROL CIRCUIT FOR A SHORT TO VOLTAGE NOTE:
Make sure the Park Lamps are off when performing this step.
- Turn the Park Lamps off.
- Turn the ignition off.
- Disconnect the Right Tail Lamp Assembly harness connector.
- Turn the ignition on.
- Measure the voltage on the (L3) License Plate Lamp Control circuit at the Right Tail Lamp Assembly harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (L3) License Plate Lamp Driver circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST
No
- Go To 3
- CHECK THE (Z917) GROUND CIRCUIT FOR AN OPEN
- Turn the ignition off.
- Measure the resistance between ground and the (Z917) Ground circuit at the Right Tail Lamp Assembly harness connector.
Is the resistance above 3.0 Ohms?
Yes
- Repair the open in the (Z917) Ground circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST
No
- Go To 4
- CHECK THE BCM FOR CORRECT OPERATION
- Turn the ignition on.
- Turn the Park Lamps on.NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
- Connect a 12-volt test light between the (Z917) Ground circuit and the (L3) License Plate Lamp Control circuit at the Right Tail Lamp Assembly harness connector.
Does the test light illuminate brightly?
Yes
- Replace the License Plate Lamp in accordance with the Service Information. Refer to LAMP, LICENSE PLATE, REMOVAL .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST
No
- Go To 5
- CHECK THE (L3) LICENSE PLATE LAMP CONTROL CIRCUIT FOR AN OPEN
- Turn the ignition off.
- Disconnect the BCM C5/E harness connector.
- Measure the resistance of the (L3) License Plate Lamp Control circuit between the Right Tail Lamp Assembly harness connector and the BCM C5/E harness connector.
Is the resistance above 3.0 Ohms?
Yes
- Repair the open in the (L3) License Plate Lamp Control circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST
No
- Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.