Anti-theft Issue

Turn the key on but do NOT crank. Does the theft light go out after a 3 second "prove out"? If the theft light does go off after the "prove out", this means the key has been read and accepted.

IF the PATS system does "proves out", then it's unlikely the reason for the no start is PATS related. Any time spent chasing a PATS defeat would likely be wasted.

IF the PATS system does not prove out, then one has to wonder if:

• There isn't something else wrong. Say a blown fuse or wiring fault.
• The person doing the PATS re-programming did not do the job correctly.
• The replacement cluster is not correct for the application. Say wrong model year or options. Remember that PATS was optional for some model years.

But in answer to your original question, yes a turner can disable PATS via a custom turn. Also, your post does not mention the exact model year of your Mustang. Why is that important? Because for the 1996-1997 model year there is an end user procedure to re-program your own keys. The procedure takes 45 minutes to complete and must be followed exactly.

Just wondering how the old cluster was fried? Could there be more damage? Say why the same thing that took out the Cluster didn't take out the PCM.

Here's a crank with no start checklist with some more information:
http://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838

Here's some information that may help to repair the original cluster:

how to fix intermittent cluster foil trace repair 1999-2004
http://www.allfordmustangs.com/forums/4-6l-tech/967186-1999-svt-cobra-trip-meter.html