I had this problem this week. Liftgate would not open with kick, fob, button or dash button. Seems like the lifters were trying to open it but latch wouldn't release. Drove home and then it started working again, then it stopped. So frustrating.
But after doing a ton of research I discovered a solution (for me), It turned out to be the battery. I had the battery replaced by a shop 2 years ago so I did not even include it in trying to diagnose. Car started fine - all other accessories worked fine except the proximity sensor to unlock the doors would sometimes take a while to work.
Well lo and behold, I checked the battery's voltage and it was 12.1V with engine and accessories off. I had just driven it a while so it should've been fully charged. From my research 12.6V is fully charged and anything under 12.4V will start to give you problems.
ALSO, and this is the important part - the shop that put in the "new" battery 2 years ago put in a standard lead acid battery from Home Depot (I did not know this until I read some topics on batteries). Turns out the Edge needs an AGM type battery with at least 760CCA. (I have A 2018 SEL 2.0L) and ALSO the BMS (Battery Management/Monitoring System) needs to be reset when you install a new battery. The car will work with a standard lead acid but it will get ruined over a year or two, has to do with the charging system and battery management.
Well, a new $300 AGM H6 48 760CCA and a BMS reset and everything is working perfectly. Even things that were intermittent like to door handle unlocking... fixed! Liftgate back to normal, even things like my a/c used to take a minute to engage when I first started the car, now engages immediately.
This is what worked in my case. I learned more about batteries than I wanted to know. LOL
Rare
Rare
