1. Check the Fuses:
* Locate the fuse box: Your 1998 Explorer likely has two fuse boxes – one under the hood and one inside the vehicle (often under the dash, near the steering column). Consult your owner's manual for the exact locations and fuse diagrams.
* Identify the power lock fuses: The manual will indicate which fuses control the power door locks. Look for blown fuses (a broken filament inside).
* Replace any blown fuses: If you find a blown fuse, replace it with a fuse of the same amperage. Do not replace with a higher amperage fuse. A blown fuse indicates a short circuit somewhere in the system, and replacing it with a higher amperage fuse could cause damage to your vehicle's electrical system. If the new fuse blows immediately, you have a short circuit that needs to be addressed.
2. Check the Door Lock Actuators:
* Listen for sounds: Try locking and unlocking the doors using the key fob or the interior switch. Listen carefully at each door for any clicking or grinding sounds from the actuators (the motors inside the door that move the lock mechanism). A weak or failing actuator will often make a faint clicking noise but won't fully lock or unlock.
* Manual override: Some 1998 Explorers allow you to manually unlock the doors from inside, even if the power locks aren't working. This helps determine if the problem is with the actuator itself or the electrical system.
* Inspect the linkage: Once you have access to the actuator (usually requires removing the inner door panel), inspect the linkage connecting the actuator to the lock mechanism. Sometimes this linkage can become disconnected or broken.
3. Inspect the Wiring and Connectors:
* Door harness: The wiring harness running to the doors can become damaged over time, especially at the flexing points where the harness enters and exits the door. Carefully inspect the wiring for any breaks, fraying, or corrosion.
* Connectors: Check the connectors at both ends of the harness for corrosion or loose connections. Clean any corrosion with a contact cleaner and reconnect securely.
* Central locking module: The central locking module (sometimes called a body control module or BCM) is the "brain" of the power locking system. A faulty module can cause problems with the entire system. However, this is usually diagnosed by a mechanic with specialized diagnostic tools.
4. Check the Door Lock Switch:
* Interior switch: Test the interior door lock switch to see if it's malfunctioning. If one door's switch doesn't work, it could be the switch itself. These are relatively easy to replace.
* Key fob: If your key fob isn't working, the battery might be dead, or the fob itself might be malfunctioning. Try replacing the battery first.
5. Consider Professional Help:
If you've checked all the above and still have problems, it's time to seek professional help from a qualified mechanic or auto electrician. They have the diagnostic tools to pinpoint more complex issues, such as problems with the central locking module or wiring harnesses that are difficult to access. A faulty actuator might require specific tools to replace properly.
Important Notes:
* Disconnect the battery negative terminal before working on any electrical components to prevent accidental short circuits.
* Consult your owner's manual: This will provide specific details about your vehicle's fuse box locations, diagrams, and other relevant information.
* Search online forums: Websites and forums dedicated to Ford Explorers (e.g., Explorer forums) can be valuable resources, with many users sharing their experiences and solutions to similar problems.
Remember safety first! If you're uncomfortable working with car electronics, it's always best to seek professional assistance.
