If it's OK when in the full headlight position and not OK when in the "park" position, then, probably, your headlight switch is defective and should be replaced.
HOWEVER!!!! If you car lights the front (headlight) parking lights ONLY when the switch is in "park", then that particular part of the circuit may have a short circuit and should be checked out before going further.
First, you have to find out what'cha got in there for a headlight switch now. Could be one of several different ones. Then, isolate the front parking light circuit from the switch and see if that cures the blown fuse. If so, find out what is causing the short in one of the headlights. Cure that and your problem is gone.