This is usually caused by a burned out bulb in the PAD switch. Ford wants you to buy a $200 switch assembly to fix it but the bulb can be replaced for a couple of bucks if you can solder.
HOW TO: Airbag light (Code 2-7) - ranger forums .com
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles
2003 XLT 2.3L M5OD-R1 reg cab beater, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid