speakers, 1988 chevy sprint

The car is a 1988 chev sprint.Randy Clark

First, who installed this unit? Second, having the speakers reversed alone would not cause the unit's failure. What can cause it to over heat is playing the radio at full blast for a long time. Or using MORE speakers than the stereo is intended. For example...the unit has four (4) channels out, one channel per speaker. If you connect all four speakers to the from two channels the unit will get hot very quickly. I think that maybe some wiring might have been damaged and that's why your fuses are blowing even with nothing plug into them. Check the "Vehicle Wiring" section above to find your wiring colors for your car and test each wire that way. Hope this helps.