hi there mate, have you been tampering with your seat and maybe unplugget the seat belt pretensioner, without having the ground terminal of the battery?
try taking the ground connection of your battery and check those yellow plugs.. If the lamp lights up with the 4 blinks then off, then 4 blinks, then its probably the other yellow plugs (for side airbags as far as I remember) under your seats that needs some love, they can get some bad connections. So, again you need to take off the ground connection on your battery, and unplug-plug the plugs for 3 or 4 times, and then connect the ground connection to your battery and see if it stills does the blinking... if this does'nt do the trick you should take it to ford and let them trouble shoot on it, since it might be something serious!

The faulty plugs is pretty common, and as written above, pretty easy to fix