Is your alarm factory installed or dealer installed. I had the problem you have described on a 2011 F150. Turned out the dealer incorrectly installed the alarm system power connection. Once the dealer fixed I never had a problem.
Thank you so much!! I have a new 2021 F150 for 3 wks, 2245miles on it. Just drove from Wyoming to LA for a funeral. No problems during trips. This morning came out - vehicle totally dead. Wouldn't respond to key fob had to enter with the mechanical key in the fob. Again totally dead, no response to anything. I put on a battery charger, showed battery 100% ok, slowly got some response on dash lights/screen but no response to starting. Called the emergency # for Ford, talked person who was to send tow truck, 4 hrs later nothing, attempted to call service dept at local Ford, voice mail and that too was filled - no body available apparently cause approaching labor day weekend. While waiting, came across your post and thought skeptically worth a try. Guess what it worked, everything ok except get a message to "turn off the ignition or start engine..". However ignition is off. So my dilemma is do I dare take into the traffic and drive back to Wyoming? Ford has had these problems but apparently won't tell us why. My local Wyoming Dealer service department that at least answered the phone - no idea and resarching problem. Again thank you.
