Circuit for air horn compressor

[JDeCourcy]

I'm installing a set of Hadley Bully air horns, and am having trouble finding an ignition activated 20 amp circuit to connect to the compressor. It draws over 15 amps. It seems the best circuit would be the cigar lighter but I can't fidure out how to access the wire. Or, has anyone used a relay to create a dedicated ignition activated circuit directly off the battery. Any help appreciated.

 

[DF5152]

i would creat a new circuit using a relay... do u plan on using ur horn switch to activate the air horn or on its own switch

 

[Glen Pratt]

I wired mine to the hot side of one of the fuel/intake grid heater relays. Power to them is on only with the key on. Works fine. I have a 12 valve though. -Glen