Electrical fan problem?

|Ok heres what happened. I installed new slimline fans that worked well for a week or two. Then I took it to the track. On the way home I noticed they weren't working. I took the electrical tape off and I had a look and the negative terminal had come out of the spade clip. I rewired it so they were all together again and tried to turn it on. Nothing. So i look at the fuse 30A and yes its blown. Ok no prob. So |I switch in a new fuse. It works. For a couple seconds then click pops the new fuse???
What the F? any ideas on what might be causing it to draw too much current now?