i wired KC lights, 2 of them, using a KC wiring harness that i got from KC. they sent it with a 30-amp relay and a 25 amp fuse. it worked for a few days then the fuse blew out. and then from there, every fuse i would put in would blow instantly. so i tested everything (nothing was shorted), and it still continued to blow. went up to a 30 amp fuse, and again, after a few days, it blew. why in the world does the fuse keep blowing ?

 

Off the cuff guess of a short somewhere in the line. Possibly at or around the relay.

 

Well somthing is shorted or the fuse wouldn't blow. Check the whole harness. Pull it out and put it back in while it's out look it over if cuts.

 

The fuse blowing is a short. It would not blow otherwise.
Maybe the wiring is chaffed and rubbing somewhere while driving. Maybe something internal in the relay.

 

ive replaced the relay and it still blows.

 

Then you have a short. Some where

 

post a picture of how you wired it.