Ive had a problem unlocking to door with either the remote or the interior door lock button. If I try to unlock the doors, the driver side door unlocks fine, but the passenger side will look like it wants to unlock, then the lock pops back down again. Or sometimes it will unlock halfway, but not enough to open the door. Every once in a while tho if I try to unlock the door while the trucks running or driving, it will unlock no problem. This is very strange to me, any ideas? Thanks.

 

In response to your problem with your lock button I may be able to help. Before I had my F-150 I had a Mustang GT that had the same problem you are experiencing with you passenger door lock. What is happening over time the rocker switch on that door has worn and the contacts are not making a good connection causing erratic behavior on that lock sometimes even screwing up the actuation of the locks on all doors. You have two easy options to fix this. First try to remove the plastic cover on the door that covers the lock and window buttons. Then there should be two screws that hold the lock button in place to the plastic cover. After removing the lock button you will see how the rocker switch just plugs into the bottom of the switch button. Pull the rock switch from the button. Inspect the contacts and see if they are worn. Sometimes you can gently bend them a bit and they will work fine again for a while. The best fix though probably about a $40 part is to just go the dealer and get a new rock switch and replace it. This should fix your problem

JSAPORIT

 

I pulled apart the switch on the driver and passenger side and everything seems fine, I dielectriced greased the terminals and put it together and its still doin the same thing. The relay is clicking fine when I try to unlock the doors. If I try to unlock and lock the doors too many times, both locks stop working. You can see both of them trying to go up or down, but they just wont work properly. Any more help would be greatly appreciated.

 

This happened to me. Its the door lock actuator. The little pump that moves the lock up and down. This happened to both my locks. Bought some for 15 a piece and fixed them myself

 

did you repair you lock actuator or replace it? I was just going to replace the actuator. I found an actuator on Ebay new for 25 + shipping, but it says it fits F150s MFG from 2/00 on up. My truck was MFG 11/99. Is there that much of a difference? This is driving me nuts.

 

I had this problem and removed them and took them apart, the 99 and 2000 locks are a bad design in my opinion. I went to my local wrecking yard and got some from a 2001 with the updated design ( this is the design they will sell you if you buy them new from the dealer) A pair of needle nose and a screwdriver and 5 - 10 minutes a side and they are done.