Mustang v6 wouldnt start yesterday, it would only do one click. got it towed home, and purchased a new starter motor, replaced the old one. Put new battery cable ends on that attach to the battery. Goto start vehicle and now its giving me errors on the dash, It says "Check Charging System" and also the anti theft light is rapidly blinking and beeping when you put the key in the on position. I've tried 10 different anti theft resets and none have worked. All the fuses and relays are good. Connections are all solid and non corroded. I'm getting discouraged because the interent has a million different things it could be. I've read it could be the PCM diode thats gone bad, or the alternator or alternator diode. I dont think i would be able to replace those. It took me a couple hours to replace the starter alone. I've read it could be the PATS ring? or ingnition switch or something. Does anyone have any ideas? Please and Thank you in advanced. I uploaded a short 30 sec video of my dash turning on so you can see. thanks

 

Pull the Cables back off and reclean them. While you have the cables off make sure the 2 fuses on the positive side are not blown.
Also make sure the connection is tight on the starter and check the other end of the negative cable. Is the Battery completely charged? That could have been part of the problem all along.
The Anti Theft light might just be the key going bad, try the other key or let the key stay in the ignition a little longer before turning it

 

I think Some Good Pics of Your Replaced Battery Ends Might Be Helpful To Diagnoses.

KC