i have a 2006 F150 Lariat 5.4L Flex 4x4 and i just learned, the hard way, that the 4x4 doesnt work at all. i tried turning the dial / switch to 4hi and 4lo but neither worked, not in drive, park or anything, even tried turning the switch to 4hi nd 4lo while truck was off nd then turning truck on but still didnt work. i think its something electrical. anybody know what i can do to fix it?

 

Does the 4WD light come on? If not, it may be the shift motor on the transfer case is jammed/stuck. You can try tapping on that with something non-metalic to see if it will come loose. Same sort of thing as a sticking starter solenoid.

 

Check your air lines.