I’m the owner of a 2014 3.7 Mustang. Over the past few months, I’ve had the “check charging system” alert periodically come on then dissappear. No issues noted. Last week it came on and remained on so I began to investigate. The only issues I’ve now noticed is the car is just slightly slower to start when it’s cold. Runs fine and starts fine once warm. I’ve also noticed the lights on the inside slight dim when you go to roll up windows or use some other applications that draws power.

I attached the multimeter to the battery and found out I was getting 15-16v. The positive terminal was so hot it melted through the plastic covering that covers the top of the battery terminal. I figured it was the regulator so removed the alternator/regulator and brought it to Oreilley. They confirmed it was bad and ordered me a new one. I installed the new alternator/regulator yesterday and I’m now getting 17-18v. The battery cables are still too hot to touch after a couple of minutes running. I took the alternator back out and had it tested, they said it was operating fine. I went and replaced the battery as well, no change in the issue. Im not really sure as to where to go from here. The only modifications I’ve done to the car is Roush axle back, CAI, and BBK shorty tube ceramic headers. The only thing I can think of now is that the heat from the headers may have damaged the wiring harness. The new headers are by no means touching it but are probably closer compared to what the stock headers were. However, I have seen no visible damage to the harness itself. I’m hoping this is not the issue as I’m assuming it’s a very expensive fix. Any recommendations?

I swapped the old battery out for a new one in conjunction with the new alternator and still have the same issue.

Any ideas of what this could be? Is there anything in particular that tends to draw more power if it’s going bad?