2021 F150 battery drain / random alarm fix

Skip to @3:37 if you're short on time.

Some door seals prevent the door ajar circuits from properly closing. With temperature fluctuations seals may expand just enough to open the circuit which sets off the alarm. An open door ajar circuit prevents the BCM from putting other vehicle modules to sleep which can cause parasitic battery drain with no DTC’s even though the vehicle appears to be locked and secure. The 360 lights staying on is not the cause of the problem, it is an effect of the problem. When service providers tell owners to turn off the lighting feature, it makes the problem harder to troubleshoot. The white lights staying on is the only visual que that a door close circuit needs attention even though all doors appear to be physically closed and the tail light circuits provide correct feedback.

With ForScan you can troubleshoot this extensively by monitoring door ajar circuits in real time or by closing individual door circuits in the BCM logic details are in the links below. Part of TSB 21-2097 includes a door alignment for this reason. A simple door re alignment can save a lot of time on this issue.

Extended discussion about this exact topic on the F150 Forums:
https://www.f150forum.com/f129/electr...

Master 14 Gen F150 ForScan Thread:
https://www.f150forum.com/f129/forsca...

TSB 21-2097:
https://www.f150gen14.com/forum/threa...