Recently I have been having issues with my battery being drained in the morning. After jumping it off first thing in the morning there is no more problems for the rest of the day. I have had the system and battery checked twice at autozone and everything is running properly. The only thing they noticed was a drain on the battery when everything was off. I recently had a portion of the wiring harness replaced (the portion that goes to the crank position sensor). There were no problems before this repair.

I would really appreciate it if anyone could help me pinpoint my issue?

 

If your altenator checks OK, I suspect your battery. With the car turned off there is some drain on the battery, just a trickle. You may need a good mechanic to see if the drain is not normal. Is you battery old and is it the size for your Mustang. Make sure the connections are not corroded.

 

All I can say is good luck. I had the same problem. Replaced the battery and the battery cable leads and did get some improvement with that (it would be dead if left alone for less than a day). I checked all the different fuses for the drain with no success. Finally I said screw it and purchased a battery cutoff switch from painless performance. It works great and I haven't had an issue with it since.

 

What you really need to do is pull your battery terminal and put an ammeter inline. If there is mmore than a couple of amps drain you then have to start pulling fuses to see which circuit is causing the drain and go from there to isolate the problem.

You would be surprised, a malfunctioning piece of stereo equipment can cause a drain. I had an Alpine once that had a fused relay that was sucking 15A when the car was off, would drain the battery overnight.

 

Thanks guys, I guess I've got some detective work ahead of me.