Battery mysteriously discharging.

[jerrywa1234]

Okay, I'm a new guy.  Joined just yesterday though we've owned our 2014 TC since new.  I'm well over 200K with a new Ford engine at 171K and transmission rebuilt at 147K.
But, recently, battery will discharge.  Sometimes overnight.  Sometimes over a few days when it sits.
Battery has been replaced though as it turns out, the 5 year old Napa unit was still good.
I finally took it to a shop and they explained that I should take it to Ford due to the fact that they think it's a BCM and as such, would have to be programmed after replacing.
Now, it is not clear that is the problem but I know you can buy aftermarket modules and have them programmed via the VIN so going to Ford shouldn't be necessary.
My problem is I'd like to be sure first before throwing parts at it.

Some research mentions door sensors.  I have not experience in testing those.
I'm wondering if this problem has been experienced by anyone here. 

[Fifty150]

On 5/29/2025 at 9:36 AM, jerrywa1234 said:

I finally took it to a shop and they explained that I should take it to Ford due to the fact that they think it's a BCM and as such, would have to be programmed after replacing.

 

 

 

Possible.  I would take it to another shop.  Get 3 or 4 shops to look at it.  Maybe one of the shops can do a computer diagnostic.  Newer cars are more complicated with different computer modules.  Or it could be something simple and mechanical.  Like an alternator not charging the battery.  Or bad wiring.