A friendly ghost?
First check if the headlight switch is in the automatic mode position. If it is switch it to "off".
Still flashing?
Pull fuse 23 in the smart junction fuse box in front of the passenger door and see if it stops. That is the fuse that powers the high beam relay.
If that does not do it leave it out and pull fuse 7, that is the drivers side low beam feed.
Passenger side still flashing?
Now the problem in both of these cases is that high and low beams both are controlled by the same part, the smart junction box. It gets a signal from the automatic light sensor and the headlight switch itself. If the switch was on auto the light sensor could be faulty. If the switch is off and you still get flashing the smart junction box is the problem.
It cannot be replaced without the proper scan tool and software as you have to pull the configuration data from it, then load that into the new module.
Being that yours is possessed you may want to see if they can tell if it is configuration data is corrupt. It will set a couple specific codes if it is.
B2A21 (One or More Configuration Files Missing or Corrupt).
B2477 (Module Configuration Failure).
If it is a dealer (and some independent shops) can contact Ford and use the VIN number to get a new copy of the data to upload into the module. It may fix the issue.
There is a TSB about the satellite antenna that can leak water into that area, you might have them look for that if yours falls in the build date range.
Water in the SJB could cause strange things.
TSB 10-4-7
03/15/10
WATER LEAK AT SATELLITE ANTENNA
FORD: 2009-2010 F-150
ISSUE
Some 2009-2010 F-150 vehicles built at Dearborn Truck Plant (DIP) on or before 1/12/2010, or at Kansas City Assembly Plant (KCAP) on or before 01/18/2010, and equipped with optional Satellite Radio, may exhibit water entry into the passenger compartment near the RH A-pillar assist handle.
Keep us updated as what you find could assist others.
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Wednesday, March 31st, 2021 AT 6:38 PM
