Tools you'll likely need:
* Phillips head screwdriver (possibly a Torx screwdriver depending on your model)
* New brake light bulbs (check your owner's manual for the correct bulb type and wattage)
* Possibly a small pry tool (plastic is best to avoid scratching)
Procedure:
1. Safety First: Park your Grand Marquis on a level surface, engage the parking brake, and turn off the ignition. Consider wearing safety glasses.
2. Access the Taillights: You'll need to access the taillight assemblies. This typically involves:
* Removing interior trim panels: There are usually panels on the inside of the trunk that need to be removed. These panels often use clips or screws. Gently pry them away, carefully working your way around the edges. Be gentle to avoid breaking the clips.
* Unplugging Electrical Connectors: Once the interior trim is removed, you should see the taillight assemblies. Locate the electrical connectors and gently unplug them.
* Removing the Taillight Assembly: The taillight assembly itself may be held in place with screws, clips, or a combination of both. Carefully remove these fasteners.
3. Replacing the Bulb: Once the taillight assembly is removed, you should be able to access the brake light bulbs. There are usually multiple bulbs in each taillight assembly – one for the brake light, one for the running light, one for the turn signal (amber), and possibly a reverse light.
* Identify the correct bulb: Make sure you are replacing the correct bulb (brake light bulb). Your owner's manual will have a diagram.
* Remove the old bulb: Gently twist and pull the old bulb out of its socket.
* Install the new bulb: Insert the new bulb into the socket, ensuring it's firmly seated. Make sure the bulb's pins are properly aligned with the socket.
4. Reassembly:
* Reconnect the electrical connectors.
* Reinstall the taillight assembly. Make sure all screws and clips are securely fastened.
* Reinstall the interior trim panels.
5. Test the Brake Lights: Turn on your brake lights to verify they are working correctly. Check both sides.
Important Considerations:
* Bulb Type: Use only the correct type and wattage bulb specified in your owner's manual. Using the wrong bulb can cause overheating or damage to the wiring.
* Grounding: Ensure the taillight assembly is properly grounded. Poor grounding can lead to faulty lights.
* Damaged Components: If you notice any damaged wiring, connectors, or other components during the process, address those issues before reinstalling the taillight assembly.
* YouTube Videos: Search YouTube for "1999 Ford Grand Marquis taillight replacement". Visual guides are extremely helpful.
If you're uncomfortable with any part of this process, it's always best to take your vehicle to a qualified mechanic. Attempting repairs beyond your skill level could cause further damage.
