My truck (2001 F-150 Lariat) had the remote keyless entry with driver's side keypad installed in the factory. It also had the dealer installed System3/System4 Ford Vehicle Security System installed (blinking red LED to the left of the steering column). The keyless entry and power door locks have stopped working. The only way to start the truck is to put the key in the ignition in the "run" position and disarm the alarm using the alarm emergency override button. I have the following symptoms:

1) The alarm automatically arms when the doors are closed
2) The truck does not respond to keyless entry pad when entering the correct code.
3) The keyless entry pad does not light up when the door handle is lifted or any of the keypad buttons are pressed
4) The truck does not respond to any of the buttons on the key fob remote
5) The door locks do not respond to the power door lock/unlock buttons on the doors
6) Entering the vehicle with the key will cause the alarm to go off unless it is disarmed using the key in the ignition and pressing the alarm emergency override button.
7) There is no door ajar or interior lights on when the issues occur.

I tried the WD40 trick on the door latches. It did not do anything.

The above problems have been intermittent but all always occur at the same time. Disconnecting the battery for awhile has sometimes fixed the problem in the past but now it appears that the problem is now not intermitent but permanent.

There is a remote keyless entry / anti-theft module mounted behind the fuse box on driver's side that has the part number 1L3T-15K602-AD.

Is this the only module that controls the power door locks?

Are there other things I should check before replacing the module?

 

did you ever figure out the issue? I am also looking for the control module