I’ve searched for hours about this topic with no luck. Vehicle was running perfect, had it detailed, drive away and the AC blows full blast heat through the windshield defrost and all lights and function to all radio and climate control **** no longer work. This lovely feature also comes and goes on its own with the loss of control and lights staying constant. Fast forward next day and the bettery is almost dead. Multi meter shows 2v. Cool it’s the original battery I bought the car with new, I buy a new one. Problem is still here so I go to research more. Next day the brand new battery is now completely dead. Check fuses, for shorts, anything left on, nothing. I don’t want to pay ford thousands of dollars to dick around. Help

 

This sounds like the alternator is dying or dead. only other thing I could think is that or there is a big short somewhere.

 

I tried my new battery for a different one and started the car fine. I could tell it was sluggish at stop signs tho and when I got home I disconnected the battery to not kill that one too. Would the alternator failure cause it to die while it’s off in the garage? That doesn’t sound right, also would it cause the AC/radio issue? Because that was still an issue with the new battery.

 

If there is a short inside the alternator, it might be causing a drain. I am not sure though.

With the car idling, do you have a meter to check the voltage at the battery terminals? Also, if you have the track apps, you can view voltage in the center display.

 

Some research shows that a bad alternator diode can cause some weird electrical problems and would explain everything. But these cars have a charging system test and I would think the warning would show up but it never has.

 

Battery and alternator passed oreillys test... no codes. I’m stuck again

 

unfortunately auto parts store tests don't mean much . . . I have had them show good when not good (battery in my case)

obviously you have a drain somewhere; I think you might need to take it to a shop that can measure and identify / isolate the drain

 

It does sound like there is a large drain somewhere. I'm still not convinced the alternator is working properly either. You said the car started fine with a new battery, then seemed sluggish at stop signs and whatnot. That indicates to me the alternator isn't doing its job well.