I'm running a positive wire from the battery, then a 15 amp fuse to my cigarette lighter because i cant find the original wire that the car came with (previous owner messed up something)

anyways i had this setup for 4 years without a problem, but then just these few days the fuse keeps on blowing. like after i put a new 15a fuse on, the fuse blows right away when I plug in a device to the cigarette lighter.

 

check the wire . perhaps it has a cut or is touching metal or something