I drive a 2003 ford mustang convertible the car has had no issues till today I am in the process of moving and on top of that I just found out my uncle died I have no money and I need my car earlier tonight I went to go dstart my car as I did I also turned on my headlights at the same time anf my car went to turn over but then nothing happen I tried to jump it off and that didn't work as I was sitting there I noticed that my theft light was flashing with the key in the ignition and without the key in the ignition I disconnected the battery and took it to O'Reilly and the did the battery test s nd it came back good I brought it back home put the battery in and now the car won't start I tried to turn my headlights on they would not come on but I would also lose my interior lights the theft lights I'd steal flashing and I have checked all my fuses and they r good can someone please help me I really need my car it's a v6 and it's a manual

 

Does it have an aftermarket alarm?

 

I've had a battery with a dead cell test good, but randomly not crank. Do you have access to another car you can take the batt out of just long enough to try in it?

 

I activated my securilock system somehow and now my car won't start does anyone know how to deactivate it or reset it

 

You need to go back to your original thread:

https://themustangsource.com/forums/...e-help-539668/

It's not a good idea to split threads like this for the same problem.

See ya in that one, ok? Cool.

 

If your PATS system (aka the SecuriLock system) is triggered and the car is disabled, there is only one real course of action:

You're getting it towed to a Ford dealer, and they're fixing it.

There is a variety of things that could be wrong, but the most likely is the ignition cylinder sensor ring is bad, and replacing it will correct the problem. But if the system has to be unlocked, and/or relearned, only a Ford approved/enabled/whatever you want to call it Scan Tool will be able to fix the problem.

There are reports of if you have a lot of other magnetic/electronic things hanging with the car's key, they can interfere and cause the PATS to be ticked off. Removing these, and just using the key may fix things.

Also, good charged battery is a key, because the PATS can be set off by trying to start with a low battery. It's interesting you don't get any headlights, as that's NOT PATS/SecuriLock related, and indicates a blown fuse or two, or the battery is actually dead, regardless of what their tester says.

Overall, though, this sounds like a dealer issue, unfortunately. I wish you luck, and hope I've helped in some small way.