Preinstallation items

For this job, you'll need some mounting brackets for all the stuff. Go to the nearest hardware store or home improvement warehouse and look for binding plates. I bought a 3" T-shaped plate and an 8 inch straight plate. The T plate will be used to mount the compressor and relay to the stock horn location. The straight plate is bent in a vice at a 90 degree angle 1.5" from one end. I bent mine the wrong way, so I had to drill a new mounting hole in the tab. If you do it right, you won't need to drill at all. The hole in the tab should be on the right as the tab faces you.

For horns, any two-horn setup should do. If you want to go three horn, you'll need to make your own bracket, and the lowest horn will probably be visible through the front of the car. I installed a Wolo horn kit just because they were red and I already had them lying around.

On to the installation!

Step 1: Remove the radiator trim and stock horn

The black radiator cover trim is all the way at the front under the hood and is removed by taking out the four screws and trim fasteners. To the left is the stock horn and bolt. Take out the bolt and unplug the horn. Throw it out into the yard.

Step 2: Assemble the compressor and relay on the bracket

Hold the bracket so that it makes an upside-down T. Put the compressor in the rightmost hole and attach the relay to the left. I made two wires with a ring terminal at one end and a female spade connector at the other, about five inches long. The ring terminals were bolted to the middle hole since the bracket connects to chassis ground, just like the stock horn. The spades connected to the compressor negative and the appropriate terminal on the relay. Consult the instructions that came with your horn to finish the rest of the wiring. Leave about 3 feet of power supply wire from the relay to run to the fusebox. We'll finish that later.

Step 3: Assemble the horns on the horn bracket

With the tab pointing toward you, put the horns on the side closest to you in the lower two holes. Angle the horns down slightly so that any water that gets in them runs out. Tighten them up and put the hoses and splitter on. Leave plenty of hose to connect to the compressor; we'll cut it later. Install the bracket from underneath and secure with a bolt trough the hole to the right of the hood release. Check to make sure the horns and bracket don't touch the hood release cable. Trim the air hose and connect to the compressor. I also used a zip-tie to secure the hose to a nearby hole.

Step 4: Wire to the fusebox

I bought an inline fuse holder and put a male spade connector on one end to connect to an empty spot in the under hood fuse box. I made a small cut in the fuse box cover to allow the wire through. The other end connects to the wire running to the compressor relay. I used a crimp-on butt connector to join the two. The fuse holder has a standard 20 amp fuse in it. The whole wire is wrapped in split wire loom, routed carefully, and zip-tied into place.

Step 5: Stand back!

They are loud. If you want to test in stages, remove the fuse to the compressor and press the horn button. You should hear the relay click.