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Problem
In the course of trying to diagnose why my passenger side intelligent door lock is intermittently unresponsive, I have come to the conclusion it is based on voltage threshold. This seems to be more of a thing with MY 2018+ based on my research. The issue seemed to raise its head after I installed my AirLift Performance 3H kit and went from very occasionally to almost 50% of the time. Also get that annoying SYNC message about shutting down to preserve battery or some such crap much more frequently. Battery tests as good for load, but when the voltage reaches a certain minimum 12.1V ish the passenger door lock/unlock from outside door handle becomes intermittent. The car has NO problem with starting.

Discussion
What steps can be taken to minimize parasitic draw when the car is at rest? Are there settings for specific electronics modules that could be modified with Forscan to reduce draw? I'm at the point now where I am considering obtaining a trickle charger to install permanently at the battery box and install a capped power socket that I can plug an AC cord into when in the garage to keep the battery topped. Anyone with insights or possible solutions?
 

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I think you hit on the real solution...setting up a trickle charger quick connect. I'm gonna have to do the same, but not for the same reasons, mine is mostly because I take such short trips that my charging system never has enough time to replace the juice in the battery. My average trip is to the store to buy groceries, 3 miles round trip, starting the car twice, playing the stereo and running the defroster/fan. And my car sits in the winter in an unheated garage. Been dealing with this since its gotten cold in Ohio lately...on a car that's not quite a year old yet.
 
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I think you hit on the real solution...setting up a trickle charger quick connect. I'm gonna have to do the same, but not for the same reasons, mine is mostly because I take such short trips that my charging system never has enough time to replace the juice in the battery. My average trip is to the store to buy groceries, 3 miles round trip, starting the car twice, playing the stereo and running the defroster/fan. And my car sits in the winter in an unheated garage. Been dealing with this since its gotten cold in Ohio lately...on a car that's not quite a year old yet.
Trickle charger? You need to find a grocery store that's further away!!! 🤣
 

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It's the battery energy conservation module (BECM) shutting down non required accessories to help prevent the battery from going dead. The first 2 things to be shut down are the start/stop function and intelligent door lock function from all do0rs but the driver's door. My 2019 edge started doing that when the battery was about 2 years old, it still passed fords fancy battery tester showing it was still good but if the car sat for 4 to 5 days the at rest voltage would read as low as 11.1 volts. I had my dealer replace the battery under warranty and the issues never occurred again before I traded it in for my mustang.

Ford Battery Monitoring System Explained In Depth By Technician (fordauthority.com)

BD
 

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I had a parasitic drain on my 2017, and after replacing the battery twice, and using a trickle charger, we found that the ground connection was loose. I had installed my UPR catch can at the ground connection, and it wasn't tight. Once it was secured, the problem went away. You may want to check your ground connections to make sure they are tight.
 
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Yes, I would agree that it is a voltage thing. In the depths of Covid when the car was sitting for extended periods I intermittently lost the touch unlock. I took to charging the battery occasionally, and then just replaced it when I checked the specific gravity in the cells and they were on the edge of fair. Probably didn’t need to but didn’t want to be stuck somewhere either, so peace of mind won out. Have never had the issue with the new AGM battery in the past year.
 

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There are threads about the catch cans that are mounted on the right shock tower at the ground wire tab stating to be sure the ground wire is placed between the tab and the catch can mounting bracket to be sure it makes a proper ground connection. Most place it on top of the catch can mounting bracket and it does not make a proper ground connection.

The screw being loose does not help either, but the wire still needs to be between the bracket and tab.

BD
 
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