fusible link??

[SS Shaun]

OK so we started working on the car the other day and i went to do some more tuning to the motor. but it didnt want to crank. Now a few weeks ago my buddy who helped me with the car put in a 20 amp fast acting fuse. the harness had something like this


I checked the fuse and it was blown. replaced the fuse with another 20amp fuse. started the motor had it running and tuned the carb some and adjusted the timing a little more. went to work on the lights that i am having issues with today and i noticed that fuse was blown again. so i started to look around and i noticed another red wire just sitting there with black tape on the end. I am guessing it goes to the little junction for the horn relay.

what should i do with this wire? what should do about this fuse issue as well?