eletrical problem
 

i have a 97 ford f250 2wd i have a problem with the running lights keeps popping the #4 fuse have replaced the headlight switch went over all wires cant find any thing put new fuse in then turn just the running lights on and fuse blows as soon as i turn the switch on cant figure out were the short is has any one had this problem if so please help i have been at this for a good while now:scare2: