Drivers side master lock switch continuously unlocks all doors so I am unable to lock the doors

Asked by Jun 05, 2015 at 11:49 AM about the 2004 Ford Explorer

Question type: Maintenance & Repair

The drivers side lock switch will continuously lock and then unlock itself when the car is
moving and even when the car is off it will continue to unlock itself. I have tried replacing
the master switch but the same problem continued to occur. I have recently disconnected
the master switch and the problem has stopped. Not sure if this problem can be because
of a broken wire or a relay. Any help would be greatly appreciated.

5 Answers

20,470

I will assume you have a remote key fob which unlocks/ locks the doors remotely. Try keeping the fob inside the house and using the car for a day without the fob attached to the key and see if the problem goes away. If it does then the problem is with the fob. The fob operates by generating a radio frequency which operates the locks. If it does not go away there could be a problem with the receiver inside the vehicle or, as you suspect, could be a short or loose wire within the system itself.

I tried what you suggested with the key fob and the problem still occured. When I was reconnecting the switch I kept the fob in the house where the signal couldn't reach the car and immediately after connecting I was unable to unlock the doors using the switch. If it is in fact an issue with the wiring where should I begin my search? Should I first look in the door panel?

20,470

A chaffed wire inside the door is usually found in the boot between the door where the hinges are located in the pillar/jam by your left foot.

20,470

The door(s) appear to only unlock themselves, not lock them. I do not have access to the diagram to your vehicle therefore I am assuming since the button on the door has to be pushed one way to lock it, then in the other direction to unlock it, the actuator works by reversing the polarity supplied to the actuator. The positive supplied to one side and the door locks, the positive applied to the other side and it unlocks. It does sound like a short or an arcing of current across two wires. If the unlocking occurs when the vehicle is parked and turned off try to notice when this occurs. Does the doors unlock, for instance, when the dome light clicks off after so many seconds.

20,470

Just thought of something, and I am not certain if it pertains to your vehicle or not, you will have to do an internet search. Some vehicles have a general electronic moduel (GEM). It has many functions and operates things like lights, chimes, etc. and is part of the ignition switch. It senses the presence of the ignition key inside the lock. On some models it will prevent the doors from being locked if the engine is off and the key still present in the ignition. This prevents individuals from locking their keys inside the car while the key is still inside the ignition. You may notice how it works in reverse. On some vehicles after the door is closed and key is turned to the "on" position the doors will automatically lock. If there is something loose or faulty inside the ignition switch it could be sending a signal to unlock the doors at random times. I do not know if your vehicle is so equipted, but is worth investigating.

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