If you blew a fuse, then you have the polarity of the leads backwards. The horns do not have a floating ground.
Do a continuity test on the leads of the horns to the mounting stud to find the ground. Then connect the hot lead to the other lead. Make sure you have identified the ground lug for both horns and connect one pigtail to each of the grounds, and the hot Lugdunum together with the other pigtail. Then make sure you connect the hot pigtail to the hot lead of the car, and the ground pigtail to the other connector.
2018 LEAF SL
Delivery April 10 2018
2014 LEAF SV
Delivery May 23 2014
50,000+ miles - all 12 bars - Same range as new - No warranty issues ever!