I own a 04, 5.4l XL.
I have the base cluster inside, crank windows, manual everything except transmission. Lol.
Earlier I unhooked the battery completely, and left it alone for about 3 hours, not intentional, just got busy somewhere.
I came back, hooked the battery up, and it won't start. Won't even crank. The gauges will will light up and go off and "tick" like you have the turn signal on. There's a small red light next to the left air vent just left of the steering wheel that blinks 5 times and pauses, then 5 times again repeatedly while I have the key in and turned. When not in, this light will light up 3 times, pause, then repeat.
The owners manual has nothing in it about my problem. Can someone help me get this started again.
And no, it is NOT the battery. Connections on the battery are perfect.

 

Pull the battery and get it load tested. Try your second key.

 

Don't have a second key.
Just one. I'm not sure if it has a chip in it. I also just noticed along with the dash blinking, the hazards are on outside the truck also. So, does that definitely point to the anti theft system being engaged?

 

You have some sort of AFTER-MARKET alarm/security system installed, none of that is factory which is why it isn't in the owner's manual. You'll need to pull the brain-box for the security system out and identify it, then find someone who understands it to figure out what's wrong.

All 99+ F150s have chipped keys. Your symptom, as reported, is not related to the chipped key or the factory PATS system.

 

What am I looking at?

 

Spending lots of money to find someone who knows what they're doing to sort it out.