Tools You Might Need:
* Screwdriver (likely a Phillips head)
* Possibly a socket wrench (depending on the bulb holder design)
* New brake light bulb (make sure you get the correct wattage and type – check your owner's manual)
* Gloves (optional, but recommended to avoid greasy fingerprints)
Steps:
1. Open the Tailgate: Fully open the tailgate of your Sierra.
2. Locate the Access Panel: Inside the tailgate, you should find a plastic access panel covering the taillight assembly. It's usually located near the taillight itself. The panel might be held in place by screws or clips.
3. Remove the Access Panel: Carefully remove the screws (if any) or gently pry off the clips holding the access panel in place. Be careful not to break the panel.
4. Disconnect the Bulb: Once the access panel is removed, you'll see the brake light bulb socket. There are typically two ways this is done:
* Twist and Pull: Some models have a bulb socket that you can simply twist a quarter turn counter-clockwise and then pull straight out.
* Push and Twist: Other models might require you to push the bulb slightly into the socket while twisting to release it.
5. Replace the Bulb: Carefully remove the old bulb. Handle the new bulb by its base, NOT the glass, to avoid getting oil from your fingers on the glass. Insert the new bulb, making sure it's properly seated and clicks into place.
6. Reconnect the Bulb and Panel: Carefully re-insert the bulb into the socket, making sure it's securely locked in place. Replace the access panel, securing it with screws or clips.
7. Test the Brake Lights: Close the tailgate and test your brake lights by applying the brakes. Make sure the new bulb works correctly.
Important Considerations:
* Multiple Bulbs: The taillight assembly often contains multiple bulbs (brake light, turn signal, running light). Make sure you are replacing the *correct* bulb.
* Grounding: If the new bulb doesn't work, double-check the bulb socket for proper grounding. Sometimes a little corrosion can prevent a good connection.
* Difficult Access: If you're having trouble accessing the bulb, consult your owner's manual or search online for videos specific to your year and model GMC Sierra. There are many repair videos available on YouTube that can be extremely helpful.
Remember safety first! If you are uncomfortable working on your vehicle, take it to a qualified mechanic.
