RE: LS door locks
WD-40 or similar penetrating fluid may help. It's worked at my dealership many times.Gently pry back the exterior glass rubber and, using the red tube that comes with the can, spray lots of fluid into the door in the direction of the latch assembly. Try spraying through the space between the front and rear doors towards the latch.
Let it soak, then gently try working the lock both from the inside handle and lock button. Be patient.
One of our trim guys has SlimJimed the locks up but this is very difficult because there's a "Antitheft plate" around the latch to prevent just such a thing. If you haven't had LS door panels apart numerous times to know exactly where to push/pull, I wouldn't bother.
When you do get into the door, you'll find a setup very different from the usual Ford lock actuator system. The actuator is integral in the latch unit. It cannot be serviced separately; the whole latch unit must be replaced.
Up here in Canada they retail for ~ $CAN 160. You'll pay much less.
Here goes a copy-and-paste:
"Trim Panel —Front Door
Removal:
Disconnect the battery ground cable. For additional information, refer to Section 414-01.
Lift the cover and remove the screws."( I can't post pictures from my inford.com manuals. What is meant is the little flip cover ~ 1"X1/2" in the armrest pull pocket.)
"Remove the interior door handle trim panel."( The rectangular trim around the interior door handle pops off if you pry gently with a small screwdriver at the lower front corner. There's a screw in behind it.)
"Remove the five screws and remove the trim panel.
Disconnect the electrical connectors." (5 screws: 1-behind the handle trim. 2,3,4-on bottom of door. 5- upper rear of panel.)
"Installation:
To install, reverse the removal procedure."
After you get in there, here comes the fun!!!
You'll have to undo the "Theft Shield" around the latch, pop off the clip for the exterior door handle rod, undo the 3 Torx screws holding the latch assembly, and disconnect the electrical connector.
Then you must weasel the latch assembly out with the interior door handle cable still attached. After you get it out far enough to see what you're doing, CAREFULLY pop the cable off. I warn you: it's fragile!
There! It's out and in your hand.