Hello all I just purchase a set of air horn and attemped to have them hooked up. The horns are 4 trumpet Air Horn that are to produces a Loud Powerful Sound of 135 dB. All the trumpets are chrome plated metal. The base is painted black enamel. This model #T-305 Air Horn Requires An On Board Air System. Comes with a heavy-duty 12 volt electric solenoid mounted on them. But when I had them hooked up the Original horn on the truck was louder. Can someone post a copy of the diagram for hooking this equipment up? thanks