Horn does not work after replacing battery clamps

Can you confirm that you checked fuse 33 for the horn? Then we need to remove the relay and take a paper clip and jump the relay from terminal 2 to 3. The horns should sound when you do it. If it does then the wiring from the relay to the horns and the horns work.

Next we need to install a known good relay (replace it), and then test voltage at pin one of the relay when you are pressing the horn.

Let me know what questions you have and we can figure this out. If all that was done was disconnect the battery and reinstalled, I suspect a fuse or relay issue but if those check out we need to work through the system an d see what we have.

https://www.2carpros.com/articles/how-to-check-wiring

While we don't recommend specific parts companies, we can direct you to different sites. This is the most commonly used parts site and has pretty far pricing.

I am not seeing any much cheaper then this but you can always look at salvage yards.

https://www.rockauto.com/en/catalog/nissan,2001,sentra,1.8l+l4,1429512,heat+&+air+conditioning,a/c+compressor,6628

Also, if you have more questions on this, we can definitely assist but we need to get a new post started because others will not find this info under this heading.

https://www.2carpros.com/questions/new