Hi all, I'm trying to help a neigbor who has a 2000 Sentra 1.8.
Her horn is not working. I searched this forum & didn't find
anything. The fuse is good. She is getting a new relay but after
searching the web, I see there is a common prob. with the wiring
scraping the radiator & causing the prob. I see people getting the
harness replaced but I haven't found anyone who said they repaired
it themselves. I'm gonna go out soon and see if I can confirm the
wire prob. I just wanted to get this thread going to see if anyone had
advice. Thanks

Nice horn, I guess, but she just wants to fix the one that's there. Thanks.

If you're like me, you're just trying to get in her pants. If I were you, I'd say something like, "Hey baby, I have a horn you can honk". Try it out and lemme know if that fixes the problem. If it doesn't, I don't think auto zone has any, but your local grocery store has a product called Bucardi Gold. It's cheap and effective. I've used it and it works every time. There are other products out there, but I like to stick with the name brands.

Dude, you're bored

I didn't see any prob with the wiring I could get to.
Hopefully the relay is the prob. If not, I'll do some
voltage checking.

trace the wires and see if they grounded out anywhere, the o2 sensor wire tends to gorund itself out sometimes on the rad fan

Run two wires from the battery to the horn, if the horn goes off you at least know that the horn is fine (if it doesn't go off you found the problem).

Do a continuity check from the NEG terminal on the battery to the ground wire for the horn, should come to something close to zero ohms. If you get an infinity reading or nearly anything above zero ohms there is a problem in the wiring, do your best to find it, if you can't just run a new ground wire to the horn.

If the ground is fine check for voltage at the horn switch, you should at least have voltage coming to it and leaving it when your press the horn button, if that is fine there is a problem in the wiring or a relay if it has one.

will do. thanks alot.
hopefully, I won't have to get to the checking
of the horn switch. I don't know anything about that.
I'll let you know.

I'm not familiar with this car but the horn switch(es) is either going to be inside the steering wheel or part of the turn signal lever assembly, most likely will be inside the steering wheel.

If you do decide to take the steering wheel apart pull the fuse for the air bag (if the car has air bags), static electricity can set off the air bag so be extremely cautious of what you touch while you have the steering wheel apart.

With that said...

The back side of the steering wheel will be where the horn switches are, they should all be wired together with a common hot wire feeding them power, check for power getting to the switches and power coming out when you press on the horn symbols on the front side of the steering wheel.

Good luck!