my GMC Sierra rear lights are not working what's the problem

Learn how to diagnose and fix rear lights not working on GMC Sierra. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked securely and the ignition is off.
• Disconnect the battery to prevent electrical shock.

2. Inspect and Replace Bulbs

• Tools Required: Socket set, screwdriver
• Remove the rear light housing by unscrewing the mounting screws.
• Pull out the bulb socket and inspect the bulb; replace if it is burnt out.
• Reassemble the rear light housing and reconnect the battery.

3. Check and Replace Fuses

• Tools Required: Fuse puller or needle-nose pliers
• Locate the fuse box, usually found under the dashboard or in the engine compartment.
• Identify the fuse for the rear lights using the fuse box diagram.
• Remove the fuse and inspect it for continuity; replace it if blown with the same amperage rating.

4. Inspect Wiring and Connectors

• Tools Required: Multimeter, wire brush (if corrosion is present)
• Visually inspect the wiring harness and connectors for signs of damage or corrosion.
• Clean any corroded connections using a wire brush and reconnect them securely.

5. Test Light Switch and Circuit

• Tools Required: Multimeter
• Turn on the ignition and set the multimeter to voltage mode.
• Probe the light switch connector to check for voltage output.
• If no voltage is detected, the switch may need to be replaced.