I searched "FJ62 Horn Fix" and "FJ62 Horn Not Working" and this is the first thread that came up so for the FJ62 owners, here are the steps for a thorough cleaning, which fixed mine. My horn would not work in any steering wheel orientation, no matter how the horn pad was depressed but I check the relay and it was getting power to the horns.
1) Gently pry the horn pad off of the steering wheel with your hands, the snap points are at the four corners, go one at a time.
2) Remove the 19mm center bolt holding the steering wheel to the steering shaft. Then remove steering wheel. I gave mine a couple of good jerks, no hand tools or specialty tools needed. Can't speak the same for other vehicles
3) I cleaned the brass ring behind the steering wheel and also the two spring-loaded contact plates (with two contact points each). These are held together by four screws with springs underneath them. I used a slotted screwdriver tip to clean the brass contact points. After this, you could put the wheel back on and without the key in the ignition, depress the steering wheel contact plate and see if your horn works. Mine was good as this point.
4) I took off my steering column cover via the screws below it. The column and the internals needed a good cleaning anyways... so I checked the contact between the spring-loaded brass contact pin of the steering column and the spring-loaded brass ring of the steering wheel. This is where folks here were "shimming" behind the brass ring of the steering wheel. I simply cleaned up the contact points.
5) Make sure you put the wheel back the same way it was before to keep proper wheel-to-shaft alignment.