i recently insalled factory fog lights in my 1998 f150 they do not work , no power to the lights. i cannot find any info on the location of the fog light relay.has anyone else had this problem. the wiring diagram that i have tells me it is in the underhood power distribution center,but the legend does not show the location of a fog light relay?

 

Most of the older models that did not come with fog lights also did come with a relay like some of the later model do. You very likely will have to add a relay.