Okay, so after recently replacing the wiring harness on my electric fan everything was running good for about a month...however, the new harness included additional grounds because the original design was not enough. After replacing the harness, the 30 amp fuse proved to be insufficient and a 35 wouldn't last long. We put in a 40 and everything ran very well for over a month but now another problem has shown up...the main power wire isn't holding up very well.

Now, the system is designed for a 30...but it won't hold up...where should I start looking in order to find out why too much power is going through? With the old harness, it wasn't grounding properly and would cook the relays...now the relay if fine but the problem is on the power wire...any ideas?

 

An electric fan should not pull more then 15 Amps. You may have a bad fan motor. The best way to check is use a DC amp meter or a multi meter in series at the fan to see the current draw.