Trying like hell to trace down my door lock problems, with no real luck, so I thought I'd post here and pick some brains here as well.

e99 truck, all doors display the exact same symptoms. For the most part, unlocking the doors is functional, but locking the doors is sporadic. It takes multiple button presses to lock the doors, the driver side does not lock as quickly as the passenger side. I replaced the driver front door with a fully functional door, locks worked on the truck it came off of, with absolutely 0 issues. I replaced the driver side rear door lock actuator. Nothing changed with either of these changes. The symptoms are identical before and after both repairs.

There was an aftermarket security system on the truck when I got it, it was a complete hackjob, it did not function at all, so I removed it. I found where they spliced the wires and reran wires from the fuse box to the door switch. - No change.
All fuses look good.

The only thing I can think of, is the actual switch itself is having issues, but I don't want to just throw parts at it if I can avoid it.

Anything else glaringly obvious to check?

 

I had the same issue with mine after doing the actuators. They worked fine for several months then suddenly sporadically then perfectly. If you look at the actuator the bottom “clip” absolutely has to be installed. I tore the door down again, remove the door handle for additional light and LOS. Sure as ****, although the actuator looked installed correctly I somehow missed the bottom clip.

 

I had my door lock actuators get weak and not consistently unlock. This link is pretty old - no pics anymore, but it's what I did to restore their function. Basically you change out a resistor in the actuator with a piece of metal. Sounds risky, but in this application, its fine, as long as you don't hold down your lock/unlock button a long time (can burn out the solenoid).
[LINK]

 

Replaced all of mine a few years ago and haven't had any problems since.

 

I've replaced my drivers door twice. It is not working again. Both of my rear doors are not working now.
I thought about buying motorcraft ones instead of knockoffs. Hoping it would solve the issue.

I cant be expected to open the door with a key....What are we, barbarians!!!

 

I’ve had a similar problem with my 2003 7.3 L lately. But my symptoms are not isolated to one door and occasionally when I start the truck up none of the doors will lock or unlock.

I’m not sure what elctronic thing is happening.