The FSM schematic shows 2 horns for my 2001.0 Pathfinder LE. I only see one ? (in front of the radiator).

Also though I haven't used horn much since I picked this Path up, except for courtesy taps, it suddenly sounds different to me - more like a motorcycle / moped horn. Almost comical. Passengers recently used some disparaging terms as to how it sounded.

I can simply put in some PIAA 85110 (400/500Hz) horns but I'm wondering if I'm missing something or if it always sounded this way or if there actually are two horns and one went out ??

Only the low-tone horn is in the grille, The high-tone is tucked into the righthand fender. See EL-380 here, E36 is low and E120 is high:
https://www.nicoclub.com/service-manual ... 1%2Fel.pdf

VStar ! My man. Thanks, it was right under my nose. When I have some time I will check the horn relay (though if one blares I would think the other would be getting juice too).

Are these repairable?

2nd Horn location --> https://imgur.com/a/Fqug5wV

The horn relay is double throw, so it is possible for one throw to work and not the other. See EL-160 for the wiring diagram. The easiest test is with a lamp between the horn wire and ground, if the circuit will light a bulb then it should also be able to blow the horn.

The horns aren't usually repairable, but there's no reason you need to use an OE part. Any old universal from Auto Zone or eBay that draws less than about 6A should work fine.

Will do exactly that, use a 12v bulb, thanks. Easier on the neighbors.
* (EL 166)

If it is the relay, are aftermarket just as good as OEM ?

Nissan's relays are all "aftermarket" anyway, they're practically all standard parts from Panduit and Omron. Nissan doesn't make any of their own electrical stuff. I wouldn't buy anything China-cheap off Amazon, but anything you get from Auto Zone or Rock Auto should be fine.

Other than PIAA not many car horn web sites have MP3's of their various model horn sounds. I would have used the PIAA 400/500Hz horns but for $60 and so/so reliability reviews I just went with the basic HELLA 012010971 twin 400/500Hz kit for $30.

I reused the stock Path horn brackets on both and pig-tailed the negative to the mounting bolt. Soldered up negative pigtail connectors and slathered silicone grease in / on all push in / bolt on connections. Used existing OEM single wire push on connections for positive.

Dirt simple install (if you don't choose to do it outside during a downpour) but the 2nd (high) horn under battery fuse box requires unbolting surrounding mounts on fuse box and/or battery / fluid reservoir to allow hand room.

Sound of Hella's is 'adequate'.