I have a '90 F250 probably a little different but there are several 3/8" (I
think) bolts on the inside of the engine compartment retaining the assembly
(head light plus the blinker) kind of a pain of the but to replace
especially after you hit a cow.  I believe that the assemblies were sealed
up pretty well it might be pretty tough to clean the lenses if the only way
to the lense is through the 1->2" hole that the light harness locks into.

You probably want to modify your address a little to prevent automated
farming from our spammer friends out there.

Ryan