1991-1994 Ford Explorer Door Lock Switch: Fixing Intermittent Locks and Identifying the Real Problem

Symptoms of a Failing Door Lock Switch

When a door lock switch begins to fail, it can cause a range of frustrating symptoms. Because the switch, the wiring, and the door lock actuator (the motor inside the door that physically moves the lock) can all cause similar problems, it's important to pay close attention to the specific symptoms.

• Intermittent Operation: The locks may work sometimes and not others. This can be caused by worn internal contacts in the switch.
• One-Way Failure: The switch might be able to lock the doors but not unlock them, or vice-versa. This points to a failure of one side of the switch's internal rocker mechanism.
• Complete Failure: Pressing the switch does nothing at all. While this could be the switch, it's also important to check the fuse first.
• Strange Noises from the Door: If you hear a buzzing, grinding, or clicking sound from inside one door when you press the switch, the problem is more likely the door lock actuator, not the switch itself. The switch is sending the signal, but the actuator is struggling to respond.
• Only One Door Fails: If only a single door fails to lock or unlock, the problem is almost always the actuator in that specific door, not the central switch.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

For a vehicle of this age, most issues are related to wear and tear rather than manufacturing defects. However, there are common failure points to be aware of.

Common Failure: Broken Wires in Door Jamb

Before replacing any parts, inspect the wiring harness that runs between the driver's door and the vehicle body. This bundle of wires is inside a flexible rubber boot. Decades of opening and closing the door can cause these wires to fatigue and break. A broken wire here is a very common cause of intermittent or failed window and lock operation and is often misdiagnosed as a bad switch.

Related Recall: Power Mirror Switch Overheating

While there are no recalls specifically for the door lock switch, NHTSA issued a recall for 1992-1994 Ford Explorers concerning the remote power mirror switch. The recall (NHTSA Campaign ID 94V060000) noted that a short circuit could occur on the mirror switch's circuit board, potentially leading to overheating, smoke, or fire. Since the mirror switch is part of the driver's side master control panel, this highlights a potential for electrical issues within the assembly. When inspecting or replacing the master switch, pay close attention to any signs of melting, scorching, or corrosion on the circuit board and connectors.

Step-by-Step Diagnosis

1. Check the Fuse: Always start with the simplest solution. Consult your owner's manual to find the fuse for the power door locks and ensure it is not blown.
2. Listen Carefully: Operate the switch from both the driver's and passenger's side. Do you hear a 'click' from the relay under the dash? Do you hear any buzzing or grinding from inside the doors? If you hear a relay click but nothing happens, the problem is downstream of the switch. If you hear noises from a specific door, that door's actuator is the likely culprit.
3. Test Both Switches: If the driver's switch doesn't work but the passenger's switch does, this strongly suggests the driver's master switch has failed.
4. Inspect the Wiring: Pull back the rubber boot in the driver's door jamb and inspect the wires for any breaks, cracks, or damaged insulation. Wiggle the harness while operating the switch to see if it works intermittently.

Buying a Used Door Lock Switch

For a vehicle of this age, a used OEM switch is often the most practical and economical choice. New old stock (NOS) OEM parts are rare and expensive, while cheap aftermarket switches can have a poor fit and feel. Here’s what to check before buying a used switch.

• Verify the Part Number: The driver's side master switch and the passenger side switch are different parts and are not interchangeable. The master switch is a large block containing window, lock, and mirror controls (Part number may be similar to F37B-14A564-AA), while the passenger switch is a smaller, single unit (Part number may be similar to F17B-14A563-AC). Always match the part to the side you are replacing.
• Inspect the Switch Action: The rocker switch should move freely in both directions (lock/unlock) and return to the center position. It should have a crisp, tactile click, not a mushy or sticky feel.
• Check the Connectors: Look at the electrical connector pins on the bottom of the switch. They should be straight, clean, and free of any green or white corrosion. The plastic housing around the pins should not be melted or cracked.
• Examine the Plastic Housing: Check for cracks or broken mounting tabs. The switch bezel is often pried out for removal, and a careless removal can damage the clips that hold it in place.
• Buy from a Reputable Source: Purchase from a seller that offers a warranty and a return policy. Since the internal electronics cannot be visually inspected, a guarantee provides protection against a dead-on-arrival part.

Installation Guide

Replacing the door lock switch is a straightforward task for a DIYer.

1. Disconnect the negative battery terminal.
2. Using a plastic trim removal tool or a flathead screwdriver wrapped in tape, carefully pry up the edge of the switch panel or bezel. On the 1991-1994 Explorer, you typically pry from the front edge.
3. Lift the switch assembly out of the door panel.
4. Depress the locking tabs on the electrical connectors and pull them straight out from the bottom of the switch.
5. If replacing just the lock switch within a larger panel, you may need to remove a few small screws holding it in place.
6. Connect the new switch, place it back into the door panel, and press down firmly until it clicks into place.
7. Reconnect the battery and test the function of the locks.

Cost Comparison

Frequently Asked Questions (FAQ)