Can't be 100% certain, but can't rule it out either. Pretty sure that's what I did to fix last time.
If its doing your head in it will only cost 33 bucks to find out. and 2 min to change. no adjustment.
https://www.ebay.com.au/itm/NEW-GENUINE-FORD-BF-FG-FGX-FALCON-SX-SY-SZ-TERRITORY-BRAKE-LIGHT-SWITCH-2008-ON-/221739182316?_trksid=p2349526.m4383.l4275.c10#viTabs_0
If you proved your lights went MIA that's the first place I'de go.