Heavy-duty pickups have more frame than any half-ton, but a conventional train horn kit still has to fight for space with the exhaust, the hitch, the spare and whatever lift you've added. A battery-powered train horn has no tank or compressor and doesn't wire into anything. You just need a dry spot for the horn and a tool battery.
What an air kit asks of a diesel tow rig
A standard train horn setup on a 3/4- or 1-ton truck is a 12V compressor, a 3-gallon or larger tank, trumpets, air line and a relay harness. The bolt-on kits for these trucks are well engineered, and every one of them still takes up room under the truck.
- Ford Super Duty: Kleinn's SDKIT17-734STL for 2017-and-newer F-250 and F-350 trucks lists at $1,399.95. The triple trumpets bolt into the factory spare tire space, and the 3-gallon tank sits on a bracket just in front of them. Kleinn says the kit was designed for lifted trucks running oversize tires, where the stock spare no longer matches. A Diesel World build on a 2017 F-250 used a HornBlasters mount in the same spare tire spot. It held two compressors, a 5-gallon tank and six trumpets. It bolted to two factory receiver bolts, and a third mounting point needed a drilled hole and a nutsert. The finished assembly was heavy enough that the crew needed extra hands to lift it into place.
- Ram 2500/3500: Kleinn's RAMHD-734 for 2014 to 2018 Ram 2500 and 3500 trucks lists at $1,599.95. It pairs a 150 PSI, 100% duty-cycle compressor with a 3-gallon tank. Diesel World's install of a triple-horn kit on a 2006 Ram 2500 put the tank on the outside of the driver's frame rail under the cab, the compressor inboard on the passenger rail away from exhaust heat, and the trumpets in the spare tire area under the bed. On the HDRams forum, one owner of a 2019-or-newer Ram HD found that their AEV lift kit already used some of the holes the horn brackets needed. Another wondered whether the brackets would land right where their in-floor storage sat.
- Chevy Silverado 2500HD/3500HD: Kleinn's direct-fit system for 2020 to 2024 trucks pairs a three-trumpet Model 730 horn with a 150 PSI compressor and a 3-gallon steel tank, and sells for $1,299.95. Like the others, it bolts to factory locations under the truck.
If you're doing the install yourself, none of this is unreasonable. But on a truck that pulls a camper or a gooseneck, everything under the bed is already busy. There's the hitch, the spare, the exhaust and sometimes an aftermarket fuel tank. If you'd rather keep the spare where it is, our guide to a train horn without deleting your spare tire covers that in detail.
What a battery horn needs instead
The Extreme Series Train Horn for Milwaukee® 18v Battery measures 14 by 6 by 12 inches and weighs 4 pounds without a battery. It runs on any Milwaukee® M18™ pack from 2.0 to 12.0Ah, and a 6Ah pack is rated for 500+ short blasts or 200 sustained ones. It's rated at 150 dB and fires from the trigger or an included wireless remote with 160 feet of range. A 2,000-foot long-range remote is an optional upgrade. It shuts itself off at 185°F, which matters if the truck sits in a sunny lot all afternoon.
That's the whole system. Nothing taps into the 12V harness, so you aren't adding load to a diesel's electrical system or splicing near the factory horn circuit. Nothing is pressurized, either, so the horn doesn't have to be bolted to the frame. It can sit in a bin, a box or on the floor.
Ford F-250 and F-350 Super Duty: under the rear seat
The Super Duty Crew Cab is the easiest of the three to sort out. Tuffy makes a welded steel lockbox for the rear seat of 2017-and-newer F-250 and F-350 Crew Cabs. It runs the full width of the cab, has more than 4,500 cubic inches of storage, and opens by flipping up either side of the seat. DU-HA makes a lockable under-seat box for 2017-and-newer F-250 through F-550 SuperCrew trucks, and Rough Country makes a molded under-seat organizer with an optional locking lid.
A 12-inch-tall horn and a spare pack fit easily in a box that size. Compare that to the spare-tire-delete installs above, which needed brackets, a drilled hole and a couple of friends to lift. Here, you flip up a seat cushion.
Ram 2500 and 3500: RamBox or the in-floor bins
Ram HD owners have a factory option no other truck in this class offers. The available RamBox Cargo Management System adds two lockable, drainable, lighted bins built into the bed rails. On the 6-foot 4-inch bed, each RamBox is 60 inches long, with 8.6 cubic feet of storage. Ram rates them for up to 300 pounds of evenly distributed cargo on 2500 and 3500 trucks. Because they drain, a horn kept there won't sit in standing water after a rinse. If you're worried about road spray, pull the battery and store it in the cab.
Inside the cab, Ram lists a fold-flat load floor with under-seat storage and in-floor bins as options on the 2500. Rough Country also sells an under-seat storage compartment for Quad and Crew Cab Ram 2500s from 2011 on. If your truck has the in-floor bins that one HDRams member worried would block their horn brackets, you can use those bins for the horn itself.
Silverado 2500HD and 3500HD: a steel lockbox
For 2020-and-newer Silverado 2500HD trucks, Tuffy's under-seat lockbox fits both Double Cab and Crew Cab. It's 16-gauge steel with more than 3,500 cubic inches of lockable space, and installs in about 30 minutes with the included hardware. That's enough for the horn, a battery and the remote, all locked away from anyone peering through the window at a fuel stop.
No lockbox? The horn can ride on the rear floor. If you'd rather keep it in the bed, our guide to a train horn in a truck toolbox or under a tonneau cover explains how much the lid muffles the sound. Either way, take the battery off when you park. Without it, the horn is just a box of trumpets.
HD fit at a glance
| Truck | Air kit example | Where the kit goes | Battery horn spot |
|---|---|---|---|
| Ford F-250/F-350 (2017+) | Kleinn SDKIT17-734STL, $1,399.95 | Spare tire space, 3-gal tank in front | Full-width under-seat lockbox |
| Ram 2500/3500 | Kleinn RAMHD-734 (2014-2018), $1,599.95 | Frame rails and spare area | RamBox bin or in-cab storage |
| Silverado 2500HD/3500HD (2020+) | Kleinn direct-fit 730 kit, $1,299.95 | Factory points under the truck | Double/Crew Cab steel lockbox |
The air kits are louder at peak. Kleinn rates its Model 730 triple horn at 157.8 dB. But they cost more than a thousand dollars, have to be bolted under the truck, and only work on that one truck. A battery horn moves to the half-ton, the side-by-side or the boat whenever you want. If you also drive something smaller, see our guides for the F-150, Silverado 1500 and Ram 1500 and for midsize trucks like the Ranger, Colorado and Gladiator.
FAQ
Do I need to wire anything into my Super Duty, Ram HD or Silverado HD?
No. The horn runs entirely on its own tool battery and fires from the trigger or the wireless remote. Nothing connects to the truck's electrical system, fuse box or factory horn.
Can I fire it from the driver's seat if it's stored under the rear seat?
Yes, if the battery is on. The included remote has 160 feet of range, which is far more than a crew cab needs. A closed steel lockbox can weaken the signal, so leave the lid open or set the horn on the floor when you plan to use it.
Will it affect my truck's warranty?
Nothing gets spliced or drilled, so there's nothing for a dealer to point at. Our guide on whether a train horn voids your truck warranty explains the rules.
Can I mount it in the engine bay of a diesel?
We don't recommend it. Lithium-ion packs don't do well in that heat, and the horn shuts itself off at 185°F. Our guide to mounting a train horn under the hood covers better spots.