Doors Unlock but Won't Lock
 

I've done some extensive searching on the forum threads and the rest of the internet to the point I've confused the heck out of myself. Here's the scenario:

2003 F-150 SuperCrew Lariat 5.4L V8, 4x2 (purchased new in June of '03)
189,300 miles

All of a sudden the locks will not lock with the remote key fob, the button on either the driver's or passenger's door, the keypad on the outside of the driver's door, or when the tranny is in drive and you take your foot off the brake.

Unlock works fine.

When pressing the lock button, I can hear a faint click coming from the driver's footwell area/under the dash. I removed the Remote Keyless Anti-Theft module and pulled the cover off it to see if that's where the click was coming from. Seems to be but not sure.

Door locks do not move when lock is pressed but move fine when unlock is pressed so I'm thinking the actuators are okay.

The switches on both driver and passenger doors light up when the headlight switch is turned on so I don't think there's a grounding problem in the doors/switches.

Battery is an Optima yellow top and is about 3.5 years old. Battery terminals/connections are not corroded. Alternator is original and I have not yet removed the connections to check/clean them for corrosion.

Anyone got any ideas or experience?

Its strange that its both at the same time. I would think your actuators are bad were it not for the fact both went at the same time but it could be.. If there bad replacing them is not easy. I've done both my doors. Did one of them myself the other the body shop that did my mustang did for me for nothing witch was nice. Gotta remove the door latch the inner panel and the outside handle. Good if you have small hands to. The part is cheap.

It's a relay inside your CSM.

https://www.f150online.com/forums/ex...m-hacking.html

Thanks for the replies. IShootStuff: I'll look at the CSM again to see if there's something I can do with it. I appreciate the link with photos.