Sounds like you have a bucket of worms. Loose and dirty connections can cause a lot of problems including blowing fuses. They cause an increase in resistance which causes an increase in amperage. If it were mine I would tear every wire out of it and rewire so I knew exactly what I had. If you don't feel comfortable doing that, at least identify the wires going to each piece of equipment, nake sure all connections are clean and tight, then get rid of all excess wires so you know they are not shorting and causing problems. Good luck.