Hi! I have a 2015 50th anniversary edition GT. 23,000 miles on it. Hadn't had any problems (except the brake screeching issue which has been fixed), but after getting back home from a 7 day vacation, the mustang was completely dead. Had it jumped, going through battery tests now at San Leandro Ford (they are excellent by the way), but are saying its fine just was extremely depleted. The advisor noticed the voltage dropped from 14 to 10 when the car was turned off. Anyone else have this same issue with the newer Mustangs?

 

I have an 09 f150 and 16 mustang that both sit for weeks at a time and I never have issues starting. Even in the winter months my f150 always starts.

I'd say you have a bad battery. If they charged the battery and it only reads 10vdc post charge that means a bad battery, it will not hold/take charge.

I know you went to the dealer, but for sh*ts and giggles, go to advance auto and have them throw their tester on it and see what they come up with.

 

What Scott said! Autozone also will test it for free. You do not have to remove it from the car. The dealership should have replaced the battery IMO. The next time it goes dead just call the dealership and let them know. The first time they have to tow it in at their expense they will probably find something wrong. battery should be reading around 13 volts without the car running and around 14 volts running.