sparks and a fried fuse
 

my radio/assy fuse holder was missing a fuse, so i went to put one in and no sooner did i touch it to the holder when i got a spark and it fried the fuse. i know i probably have a dead short somewhere but so far no wires bare anywhere. no radio in yet either. can anyone kind of narrow this down for me? / also i found a radio wiring harness made by metra with the dates 1979-1989 for an rx-7will this work in an 83 ltd ed. would really like to know about the 2nd question so i dont waste my cash on this item? appreciate any feedback

check for a penny in the cig lighter. Make sure there are not any bare wires that are causing the problem.