Got the Shocker 228 conductor special on the car yesterday, everything set up correctly we are pretty sure but when the compressor is filling up the horns are blowing air. We rewired the solenoid in everyway possible and even tried grounding the wires but that didn’t work. I read somebody had the same problem, a “hissing noise” and his horn diaphragms were dirty and had water on them but these are brand new horns and shouldn’t have dirt. It seems like the solenoid valve is not closing or something.
So the solenoid valve is letting through air?. Check it with both wires disconnected and make sure you have it hooked up to the airflow in the right direction (the valves are only designed to flow air one way )
Welcome. Could forzen moisture be causing the solenoid to stick open?
I had the same problem. Flip the solenoid around. Make sure the arrow is going the right way. I installed mine at night so I couldn’t even see the arrow.
Solenoid has to be the right way round else your horns with start humming as you fill the tank:)