99 Limited - door locks unlock, but won't lock

[snobiz]

1999 Ford Explorer Limited
I have a power door lock problem that I haven’t seen anyone else having on this forum. The driver & passenger door lock buttons, exterior keyless entry pad and the hand held remote won’t lock the any of the doors, but will unlock them, with one exception. The button inside the rear hatch door will lock and unlock all the doors. The problem started when the truck was not run for three weeks. Before the three week rest, everything worked normal. The reason for the three weeks of non use was due to a stuck cooling system thermostat causing the engine to overheat, which I finely had time to replace this week. I’m thinking if it was a power lock relay, then none of the buttons should unlock the doors either. Can anyone give me some ideas as to what may be causing this problem?

[taz4x4150]

Any other symtems? I have read other posts where a low/weak battery will do funny erratic things to power locks/windows. Since it sat for 3 weeks without being charged by alternater it could have lost power. How old is your battery? Take it somewhere(Autozone) and have it checked.

[snobiz]

The battery is old and should be replaced before winter. I've owned the vehicle for three years. I bought it from my Father-in-law who was the original owner and I don't know if he ever replaced it. One would think he would have replaced it at least once. I drove it about 10 miles after the repair and I ran it for 30 minutes in the driveway to make sure the overheating problem was fixed. Other than the lock problem, everything works correctly, the engine starts easily and runs very well. No other symptoms that I can notice.

[98ExplorerMan]

Originally Posted by snobiz

1999 Ford Explorer Limited
I have a power door lock problem that I haven’t seen anyone else having on this forum. The driver & passenger door lock buttons, exterior keyless entry pad and the hand held remote won’t lock the any of the doors, but will unlock them, with one exception. The button inside the rear hatch door will lock and unlock all the doors. The problem started when the truck was not run for three weeks. Before the three week rest, everything worked normal. The reason for the three weeks of non use was due to a stuck cooling system thermostat causing the engine to overheat, which I finely had time to replace this week. I’m thinking if it was a power lock relay, then none of the buttons should unlock the doors either. Can anyone give me some ideas as to what may be causing this problem?

I just bought a 98 Explorer with the same problem. I wonder about the battery being the culprit if the Rear Lock switch functions correctly and the Front
Door switches don't.

[snobiz]

What I've discovered so far.... It's not a bad switch on either door. A Friend of mine has access to All Data at his work and looked up the wiring diagram covering the locks. If he is reading it correctly, the rear switch is on a separate circuit and doesn't use the lock relays. There are separate relays for lock and unlock. As soon as I locate where they are, I'll replace them. If that doesn't fix the problem, then the problem is probably a cracked wire in the door harness where it goes from the door to the body.

[98ExplorerMan]

Let me know what you find out, having to open rear glass to lock the doors is getting old...

[theoldwizard]

Originally Posted by snobiz

I’m thinking if it was a power lock relay, then none of the buttons should unlock the doors either.

Check the voltage at the actuator. If it is close to the battery voltage you will probably have to buy new door lock actuators. They get "tired" over time and just do not have the torque required. (There is an internal resistor that prevents them from drawing too much current, which alos limits their power.)

About $35-45 each on eBay.

[98ExplorerMan]

Snobiz, the problem may be at a splice point at the under the rear of the LH Rear door threshold. Check out this thread Door Lock Problem - Ford Explorer Ranger Enthusiasts "Serious Explorations"® , It worked for me.