Method 1: Access from the Trunk/Cargo Area (Most Common):
1. Open the Trunk/Cargo Area: Access the rear of your truck.
2. Locate the License Plate Light Assembly: The light assembly is usually located near the license plate itself. It might be a single unit or two separate units, one for each side of the plate.
3. Remove the Lens: This usually involves one of the following:
* Twisting: Gently twist the lens (often counter-clockwise) to loosen and remove it.
* Pushing and Pulling: Some lenses might have clips or tabs that need to be pushed or pulled to release them. Carefully inspect the edges of the lens for release points.
* Screws: In rare cases, small screws might secure the lens. Use a small Phillips or flathead screwdriver as needed.
4. Access the Bulb: Once the lens is removed, you should see the bulb socket.
5. Replace the Bulb: Carefully remove the old bulb (usually a wedge-style bulb). Important: Handle the new bulb by its base, not the glass. Insert the new bulb into the socket, ensuring it's properly seated.
6. Reassemble: Put the lens back in place, making sure it's securely fastened. Test the light to verify it works.
Method 2: Access from the Inside of the Truck (Less Common, but Possible):
Some GMC trucks might require access from inside the truck bed or cab. If the first method doesn't work, you might need to:
1. Look for Access Panels: Examine the inside of the truck bed or the back wall of the cab near the license plate area. There might be small access panels or removable trim pieces.
2. Remove the Panel: Carefully remove any panels or trim that block access to the light assembly.
3. Follow Steps 3-6 from Method 1: Once you've accessed the bulb assembly, follow the same steps for removing and replacing the bulb.
Troubleshooting:
* If the bulb doesn't work: Double-check that the bulb is properly seated and that the new bulb is the correct type.
* If the socket is broken: You might need to replace the entire light assembly.
* If you can't find an access point: Consult your owner's manual or search for repair videos specific to your 1998 GMC truck model and trim level (e.g., "1998 GMC Sierra license plate bulb replacement"). YouTube is often a great resource for this.
Important Note: Always disconnect the negative battery terminal before working on any electrical components in your vehicle. This is a basic safety precaution to prevent shocks or short circuits. If you're uncomfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic.
