How to Fix the Horn on a Ford Rangerby Jeffrey Caldwell
A nonfunctioning horn on a Ford Ranger could be caused by three possible culprits: a malfunctioning horn, horn switch or a blown horn circuit fuse in the fuse panel. Automotive electrical troubleshooting can take a little time and patience, but fortunately, it is within the abilities of most amateur mechanics.
Testing and Replacing the Horn Circuit Fuse
Remove the fuse for the horn circuit from the fuse panel. It should be rated to handle at least 20 amps.
Check that the metal bridge between the two terminals is intact.
If the fuse is blown, replace it and test the horn for proper operation.
Testing and Replacing the Horn
Locate the horn. If the fuse is not blown, or you've replaced the fuse and the horn still does not function, you must check the horn itself. The horn will be attached to the radiator core support.
Label and remove the two wires connected to the horn.
Test each wire with a 12 volt test light. Connect the ground clip on the test light to the negative terminal on the vehicle's battery. Have an assistant sit in the vehicle and operate the horn switch on the steering wheel. Touch the probe on the test light to each of the wires as your assistant pushes the horn.
Find the ground and positive leads. One of the two wires will be a positive lead, and cause the test light to light up when the horn switch is pressed. The other will be a ground, and will not cause the test light to light up. The ground lead is the wire that will be connected to the vehicle's body.
If the test light does not light for either wire, there is a problem with the positive lead. Trace the wire as far as you can and look for breaks, kinks or wear. Replace the wire where necessary.
If the test light illuminates while connected between the positive and negative leads, the horn itself is bad. Remove the bolts that connect it to the radiator core support and replace it.
If the test light stops lighting up while connected between the positive and negative leads, the ground wire is bad. Follow the wire from where it connects to the horn to where it connects to the vehicle's body. Look for any breaks, kinks or wear in the wire, and replace as necessary. Also examine where the ground wire connects to the vehicle's body. If there is rust or corrosion present, it must be cleaned so that the ground lead comes in contact with bare metal.
Testing and Replacing the Horn Switch
If the horn circuit fuse is intact and there is not power reaching the horn itself, the most likely culprit is a faulty horn switch.
Remove the steering wheel hub cover by either pulling the hub emblem off, or removing the screws from the back of the steering wheel and pulling the hub cover. This will depend on the year and trim level of your vehicle.
Connect the ground clip on the test light to a metal spot on the vehicle's body. Do not connect it to any of the metal brackets supporting the dash.
Test the two terminals on the horn switch with the ignition switch in the "run" position. One of the terminals should cause the test light to light up.
If the positive lead to the horn switch is working, the horn switch must be replaced. Label and remove the wires from the horn switch.
Remove the horn switch from the steering wheel.
Install a new switch.
Connect the two wires to the new horn switch.
Reinstall the steering wheel hub cover.
- The ignition switch must be in the "run" position to properly test the function of the horn, horn switch and wiring.
- On airbag equipped vehicles, you must disconnect the airbag before attempting to service the steering wheel. Failing to do so could result in injury or death.
Items you will need
- Socket set
- Twelve volt test light
- Phillips screwdriver
- Flat blade screwdriver
- Replacement 20 amp fuse
- Replacement horn
- Replacement horn switch
- "Chilton's Ford Ranger/Bronco II Explorer 1983-91 Repair Manual"; Chilton Book Company; 1991
- "Haynes Ford Ranger Bronco II Automotive Repair Manual 1983-1992"; Chilton; 1999
- Zepfanman - creativecommons.org