JC Whitney Electric 12 15 Psi Air Compressors for Air Horns "horn compressor working" Questions

...box ( or in line fuse to batt positive ) & --- # 87 to the horn compressor,then # 85 to a button inside the vehicle............ some off those chines relays work backward or are

...compressor designed to supply a manufacturing process. Used equipment might be available somewhere near you. I can't really comment further without knowing the purpose, whether it is fixed or mobile ...