Did you check the whole cable or just the connections? Since the wire has been in for so long, it may have rubbed somewhere and grounded out somewhere. My advice would be change out the cable and see if the problem still exists. Worst case there, you're out a bit of cable and some connectors. If not, I'd start looking into the PSU to see if it's drawing extra current for some reason. Start with the easiest to check and replace first though which is the power line.