Air Horn Sizes
Air horn dimensions are diverse. Some models measure 
2-1/2" W x 4-1/2" L x 4-1/2" H, while others are 3-1/2" W x 5-1/2" L x 5-1/2" H. The decibels of these models also vary. However, many of them can be used on different types of vehicles. Installation is also the same regardless of the vehicle.
How to Install an Air Horn
Required Tools and Materials
- Nylon wire ties
- Multimeter
- Screwdriver
- Drill
Step 1
Open the hood and look for a place to put the horn. Make sure the horns are at a downward angle so water doesn’t gather. The horn should be put toward the front of the car. Don’t put the horn near an area where it will get too hot or too much moisture.
Step 2
Use the self-tapping screws to mount the horn. Use the included mounting hardware. Place the compressor to firewall. Set the tubing from the compressor to the horns. Do not run the tubing close to moving or hot components.
If possible, have the tubing run with factory wiring harnesses. You can fasten it with the nylon wire ties. This should be done regardless of the air horn dimensions.
Step 3
Get the multimeter and examine the horn wire. It should register 0 volts at rest and 12 volts if the horn is pressed. This wire is at the horn or the horn relay. Hook up the horn wire with the relay with power.
Connect the 12 volt output on the compressor. Follow the instructions as indicated in the air horn package. Usually, Pin 87 is to be wired to 12 volts. Pin 86 is to the ground and Pin 85 onto the horn wire. Pin 30 is for the compressor positive lead.
Step 4
Position the compressor on firewall or somewhere far from water or intense heat. Join the negative terminal to the compressor to ground.
Step 5
Test the horns. If the installation is correct, the horns will sound correctly. If it doesn’t, go over the process again and see where you went wrong.
Tips and Warnings
Always put a fuse to the 12 volt power wire. This will ensure no components will get damaged or broken.
No matter what the air horn dimensions are, these horns will be louder than the ones that the one that came with the car. Use the horns only if it’s necessary. Make sure that the horns’ decibel level is within the city regulation limits.
