Need help in this heat wave. 2006 Mustang V6. No A/C..dealer replaced a fuse under the hood and it immediately blew. Stated he wanted $700 to replace the large black fuse box on the passenger side under the hood. Did some checking and there is no power to the clutch. The 5A fuse under the passenger dash is good. Now the fuses in the underhood box are all good. Swapped the high-beam relay for the A/C relay and no change. Why doesn't it blow the fuse anymore or did the dealer take out the one that blew. Any help appreciated.

thanks!

 

Some other short on that circuit. Most likely, O2 sensor or wire. Had a similar short on my V6.
The same power that feeds the a/c clutch also feeds numerous other circuits. You'll probably get the check engine light at the same time if that shared fuse blows.

If that fuse is not blowing, though, you have other issues.

Replacing the 'black box' (the bec, bussed electrical center) wont fix your issue unless a short has been diagnosed internal to it. Such diagnostic has not likely been done.