Whelan Engineering's 200 Watt 12 Volt siren heads are designed to be mounted directly onto the dash or other surface with a bail strap bracket. Some vehicles can be supplied with a suitable console that the siren head can be installed into, and mounting kits are available that include all the necessary hardware. Once you've installed the head unit you will need to wire it. Wiring involves connecting power and ground wires, speaker wires, horn relay wires and optional radio re-broadcast wires.
Connect the power and ground. Splice the two red power wires together and then extend the single red wire towards the battery. Do the same with the black wires which will be the ground wires. Install the fuse block on the end of the red wire and remove the fuse. Connect the fuse block wire to the plus terminal of the battery. Keep the wire length below 2-feet here. Connect the ground black wire to the chassis.
Connect the orange wire to the positive connection on the speakers. Connect the brown wire to the negative connection on the speakers.
Wire the horn. Route the white and grey wires to the horn relay. Cut the wire that runs between the horn to the horn relay and connect the white wire to the wire protruding from the horn relay. Then connect the grey wire to the wire that comes out of the horn.
Connect the vehicle's two-way radio to the external speaker if you would like that feature. Cut the two wires that connect the external speaker to the radio. Splice one of the blue wires into the circuit. Then cut the remaining speaker wire and splice the remaining blue wire into that circuit.Re-insert the fuse.
