Installation Guide for Miata Stebel Airhorn Kit

Before beginning, disconnect the negative lead from the vehicle battery. If you have a factory radio, make sure you first record the security code! Once that's out of the way, pop your hood. Your Miata may have a plastic cover over the area in front of the radiator. If so, it's usually held in place with 4 plastic fasteners - see the picture. From the top it looks like those are screws, but they are really just threaded plastic expansion fasteners. They work by using a center plastic pin that pushes down and forces apart two plastic arms that then holds the position by friction. To remove, first try gently backing out with a phillips head screwdriver. Don't apply too much downward pressure. If they've been taken out more than once or twice, the plastic threads may be stripped out. Use a small flat blade screwdriver to gently pry the center piece upward. Once exposed, you can pull it with a pair of pliers or lever it completely out with a screwdriver. Set the cover and fasteners aside.

Now locate your old horn. It is mounted on a bracket next to the hood latch. Remove the single bolt that holds the horn bracket and lift the horn upward being careful not to break the attached wire. Remove the single wire that connects to the horn. It's a push-on spade type connector. If it's rusty a needle nose plier will help get it off. Note that the horn location gets a lot of weather and heat and it's not uncommon for the wire to have been spliced or repaired over the years. If your horn wire doesn't have a normal spade lug at the end, you'll need to attach one. You can get spade connectors and crimpers at any Radio Shack. Set the old horn aside.

With the old horn out of the way, you can now see the new mounting area. At this time you might wish to remove your front license plate mounting bracket (if so equipped) as the new horn will have to be inserted from below.

Note that on some Miatae you may find your horn wire fastened to the frame with a stick-on tape. Depending upon the length of your horn wire, you may need to pull the wire loose from this area in order to get sufficient length to attach to the horn.

Take the horn body out of the package. From the horn package you'll also use the small rectangular black plastic mounting spacer (if included - newer stock from Stebel don't include this piece), the bolt, and nut provided (pictures to the left of the horn). The 3rd Millennium Miata kit includes a green or black 9" wire, an aluminum mounting bar, a 1/4 x 1" hex mounting bolt, 2 lock washers, and a 1/4" nut.

Take the large bolt, plastic spacer, and nut that was in the horn package and the aluminum spacer, and assemble them as in the picture. If your kit doesn't have the plastic spacer, the aluminum bracket should be placed directly against the aluminum frame of the horn body. The bracket should be facing straight upward. Tighten the nut securely with a wrench once you have it set. See the next picture for another view.

Rear view of assembled bracket

Front view of assembled bracket

This is probably the hardest part of the job. Take the bolt and one lock washer and insert it through the new mounting hole location from the rear. This is tough as there isn't much room to fit your hand. If your Miata has AC, there will also be a tube running right in the area where you'll be trying to position the bolt. It will fit - really. Angle the head of the bolt upward and the threaded end downward and you'll be able to slip it behind the frame and then work it forward into place. In the picture the installer held it between two fingers, got it behind the mounting hole, and then held the bolt like a cigarette lightly between his fingers and worked it into the hole. You can also try holding the bolt with a needle nose pliers from below. Be patient and expect to drop it a few times! It will fall down onto the plastic shield that covers the bottom of your Miata's engine area and you can usually reach in and grab an item you drop. TIP: place a towel below the horn area to catch any dropped parts.

Success! The trick now is to be careful not to knock it out as you complete the rest of the installation.

Tip: an assistant might help if you're having trouble installing the bolt. They might have smaller or more flexible fingers or can try reaching up from below to insert the bolt while you work from the top to grab it.

Holding the horn, take the green or black ground wire and attach it to the '-' terminal. The plus and minus are marked by symbols embossed into the plastic housing. Only one end of the wire can attach to the terminal so it's impossible to get it backwards.

This steps requires some flexibity. Take the horn and insert it through the nose opening and then upward toward the mounting location. Be patient. It's awkward but the horn will fit in and you will be able to move it around into the necessary position. Once you have it in place so that you can see it from above, turn it so the terminals face upward. Take the Miata's '+' lead and attach it to the plus terminal on the horn. Then carefully so as not to pull on the wires, turn the horn over so that the bracket points upward toward the mounting bolt. If you have long arms this will probably be easiest to do by reaching from underneath. An assistant is helpful for this step as it's hard to see the mounting bolt from below. If you have a shorter reach, we suggest having one person working from below and the assistant guiding the assembly toward the mounting bolt. Be careful not to knock out mounting bolt you worked so hard to position!

Carefully work the hole in the bracket up over the mounting bolt. You don't want to push the bolt out!

With the bracket on the bolt, fish up the end of the green or black wire supplied with the kit and place it over the bolt. Then place a lockwasher on the bolt and finally the nut. Hand tighten the nut.

Tighten the nut with a wrench. If you had to remove a cover over the hood latch area you can reinstall it. Reconnect the battery and give it a test. Wow! That will get other driver's attention!