I had a 1981 Buick Electra Park Ave. It had the four note horn option that was also available on Cadillac and Olds. That horn was really loud and had a train like tone to it. Rather amazing when you consider it was just four electric horns. I pulled them from it when I scrapped the car and put them in my truck, really great for a cheap horn. When I picked up my new truck I went on e-bay and bought a set for $100, I bought the newer ones from the newer style (mid Ninties I think), pretty good too, but a little smaller size and also not quite as loud. I'll do it again when I get a new truck but I'll look for the older bigger style from the early eighties cars.

I have two piggieback kl5a,s under the bed of my truck and nitrogen tank like yours with a regulator and all 1/2" lines. I started with the manual hand valve in the truck.....and believe it or not, I like the tone best regulated at 86psi. What makes the hand valve so cool is the ability to manually regulate the volume of air so the tone changes as you pull harder........
w w w w wwwwwWWWWWWWWWWAAAAAAAAAAAAAAAAAAAAANT

As you are thinking, I though of putting an electric solenoid hooked to a switch. I lost the ability to honk Like a train.....slow start to full blast....but it was cool to WHATWHAT instead of pulling the lever

Last month, I changed from compressed air to nitrogen and a bizarre issue developed. The solenoid hangs on the nitrogen and repeatedly hitting the button as well as killing power completely does nothing. My horns are so loud that the t handle on the regulator vibrates and backs out, and when the pressure in front of the solenoid gets to about 30psi the solenoid finally releases.....but that takes about 10-12 seconds of continuous full on honk.

I do oil my system at tank change which is only about every 7 months....seriously considering going back to the manual valve.

Either way.....this is the way to do it. The other guys around town blow their horn and it's done in a few seconds. I could blow mine for hours before I run out of air!

I'm betting your issue with the solenoid sticking when you went to nitrogen was the pressure. Your compressed air system might be 150-200#, but the pressure on a nitrogen bottle is in the 2,000 - 4,000 # range. Your solenoid valve probably isn't rated for that, unless your using a regulator out of the bottle, knocking it down to a decent working pressure.

He's running a regulator you have to with nitrogen tanks. Now I do know that nitrogen is a dry air that's why we use them at work, your compressor with have moisture unless you install a dryer of some sort like what people use on paint guns. Don't know if that could be a problem for you.

My switch actuator just $hit on me about after the 5th hit, the gasket is leaking, could be from age, or possible not rated that high. How much does it cost to fill your tank?

I forgot about these horns. I just bought a set on eBay to put on my daily driver sedan.

Are these horns normally hot and switched ground to activate;
...or apply 12V+ to activate like most 12V accessories?

(My F-350 was the former which surprised me when I was adding my train horns.)

I did not check, or switch these seperatly as I wanted the steering wheel horn button to activate them. In both cases I just split the wiring on the truck going to the stock two horns into four and hooked them up.

My dad had a set on his old S10 pickup, I used to sit at the train tracks and hit them when someone was getting ready to cross. I know not very nice, but it was hilarious to see their reaction.

Installed them on my daily beater this weekend and promptly blew the factory fuse. :D
They don't compare to the train horns on my dually, but I do feel like I am driving a 1980s Estate Wagon when I hit them. I've got them hooked up with the factory horns, so now six total.

Can anyone recommend a set if horns in the $150 to $200 range. My step son wants a set for his beater for christmas. Thanks

This is fair for the price IMHO; and the seller was easy to work with. I ended up buying outside of eBay which saved me a few bucks.
http://www.ebay.com/itm/Loud-145dB-C...item1e83cc4fa4