Thanks for any help or direction you can give me.

1999 F150 Lariat 4x4 with 5.4 engine. Been having problems with starting the truck. I really feel this is a problem with the anti-theft "feature". Right now I've got the battery charger on the truck (too many non-starts) and the Theft light is solid. I've seen it blinking before when trying to start and now I'm confused on what it's supposed to look like.

The manual says:

Theft indicator
The theft indicator on top of the instrument panel will operate as
follows:
² When the ignition is OFF, the theft indicator will flash briefly every 2
seconds to indicate the SecuriLocky system is protecting your
vehicle.
² When the ignition is turned to ON or START, the theft indicator will
light for 3 seconds and then go out. If the theft indicator stays on for
an extended period of time or flashes rapidly, have the system
serviced by your dealership or a qualified technician.

So, now I've got the battery charged and the Theft light solidly on. What steps can I take to fix this problem without having it towed to the dealer to fix? And if I can get it started, are there any troubleshooting steps I can take to see what got me into this problem in the first place?

I've left the key in the run position for 5 minutes and got no change to the steady on Theft light. Disconnect the battery for a day? Would this have any effect?

Thanks again.

 

There is a problem with the PATS system.
You will need the services of a dealer.
You can't normally make a difference by powering down unless the problem is intermittent.
.
Basically the PATS has to work correctly from the key insertion code being recognized to the PATS sending the correct coded signal to the PCM where it allows the PCM program to allow staring the motor.
If it did not work to this level the PATS would be all but worthless for theft protection.
It gets so involved with programming and equipment that you can't handle it.
Good luck.

 

I'll assume you tried your spare key already?

 

Still solid Theft light. Yep, been trying both keys to see if I could get any change.