Ok so I have the Blackbear tune/mods for fans, 185 thermostat, spin tech exhaust and a LS1fans harness.
At first it worked great! 1 fan came on with a/c etc....a couple of weeks go by and I see the temp gauge climbing near 230 so I shut it down and 1 of the 2 40amp fuses is blown. Replace fuse and back in business. It keeps popping a fuse after a few weeks to a month. I had new Dorman fans and we thought this was the isue a bad fan so I am on my 3rd set of fans and I know have OEM gm dual fans that work correctly. Checked all the connectors behind the relays for proper connections.
Checked my ground wire, + wire, plugs are all in.
I only have about 1500 miles on this set-up live in so-cal so not crazy hot.
Any help would be great!

 

You did not mention what you drive or which harness you purchased from them.

However, it's probably a stuck or sticking relay keeping the fan on all the time and melting the fuse.