2002 Buick LeSabre horn relay replacement

It's in the underhood fuse box. See the diagram on the fuse box cover. Wiggle the old relay up and out. Find a replacement at any auto parts store.

You can swap it for a similar fuse to see if that's the problem . Get a multi tester to see if the horn is grounded and has power when you blast it . Hit ti with a hammer see if that helps , (seriously )

Most horns are darned resilient and rarely die. It is more often a bad connection or worn out switch (though technically, a worn out switch is also a bad connection). On my LeSabre, I have to push the center of the steering wheel pretty hard to get the horn to honk. No joke, by the time i get it to honk, the moment has usually passed and the point is moot. I have found that it is more likely to work if you press right on the little horn symbol on the steering wheel. Though, in the heat of the moment you really can't be bothered to find the little horn symbol, can you? If that does not solve the problem then go check fuses. I don't recall if the horn fuse is out under the hood or under the rear seat (there are fuses at both locations). If you have ever changed the battery you already know this because it is also under the rear seat. And getting the rear seat up can be quite a job in itself (I dont replace the screws that hold the rear seat in secured...they seem to be overkill to me...the seat stays in place just fine without them). If the horn fuse looks good you will need to get a tester to check for electricity at the fuse. You can get a little light up electrical tester for about 10 bucks at wally world or any auto parts place (you can make your own if you have a spare 12volt bulb, a little wire, and a soldering iron laying around). Check for power at the fuse when you push the horn. You can use stick or something wedged between the driver seat and the horn to actuate it as you are doing the electrical testing (or find a helper to press the horn for you). If you have power at the fuse then next check for power at the horn. If you have power at the horn, then check for a good ground at the horn. In my experience, many horns only have 1 wire going to them and they get their ground from their mounting bolt(s). So need to check that carefully. Of course the final thing you can do is remove the horn assembly and hook it directly to the battery to see if it works. Possibly that test should be done first. Depends on the vehicle and ease of access.