2001 f150 no start

my 4x4 light quit in my 2001 supercrew f150.changed it now the truck will crank over but wont start any ideas out there?i was thinking some thing to do with the anti-theft.but i dont know how to reset it.tried unhooking battery for 1/2 hour still nothing

Is the "Theft" light flashing rapidly? How did you "fix" the light?

pulled the instrument cluster out & replaced the 4x4 light w/the ingnition off it it flashing rapidly

If the THEFT light is flashing rapidly, then there is a problem with the PATS anti-theft system. It will need to go to a dealer.