Train Horn for a Toyota Tacoma, Tundra, or 4Runner: Why a Battery Horn Gun Beats Squeezing In a Tank Kit

Owners of a Tacoma, Tundra, or 4Runner hit the same wall when they shop for a train horn: the kit pages are written for half-ton trucks with room to spare, and a mid-size Toyota does not have that room. Here is what a tank-and-compressor kit actually asks of each of the three vehicles, and why a battery horn gun that rides behind the seat is the easier answer for most of them.

The short answer

A vehicle-specific air kit for a 2016 to 2023 Tacoma lists at $1,299.95, the older-generation Tundra kits start at $1,199.95, and the main direct-fit maker lists no kit at all for any 4Runner or for the 2024-and-newer Tacoma. Every version needs a tank and a compressor mounted on a vehicle with no free engine-bay space, a tight spare-tire crossmember, and, on the hybrids, a battery pack under the rear seat. A battery horn gun costs $270, produces up to 150 dB, runs on the cordless-tool pack you already own, and needs no wiring, no drilling, and no tank. It works on all three vehicles the day it arrives, and it moves between them.

Our general comparison of a horn gun versus an air-tank-and-compressor kit covers the trade-offs for any vehicle. This article is about the packaging problem on Toyota's trucks and SUV.

Why a mid-size Toyota is a harder kit install than a half-ton

The demand is real. Toyota sold 274,638 Tacomas in the US in 2025, a record and a 42.4 percent jump over 2024, plus 147,610 Tundras and 98,805 4Runners. But the install playbooks written for full-size pickups assume space these vehicles do not have:

• The engine bay is full. On a Tacoma the cooling stack, intake, and accessory drive fill the bay, so there is no room for a 2-gallon tank plus a compressor up front. Trumpets can go in front of the radiator, but everything else has to live elsewhere. Owners who did go under the hood fit a compressor behind the grille, never a tank.
• The spare-tire crossmember is the default, and it is tight. The standard answer is a flat bracket bolted to the frame rails in the spare-tire location under the bed. One Tundra owner who packed a direct-fit kit in front of the rear axle called it "a lot to tuck in there but it does fit," and a second owner with dual exhaust had to remove the spare entirely. On the Tacoma forums one owner asked whether a 2.5-gallon tank fits under the truck with the spare in place; another skipped the question and put his compressor and tank in a bed toolbox.
• The bed is composite, not steel. Tacoma beds and the 2022-and-newer Tundra bed are molded sheet-molded-compound composite. Owners who have drilled it say it cuts fine, but they back every hole with a metal plate or large washers, and several recommend D-rings on the existing bed bolts instead of drilling at all.
• The hybrids took the under-seat space. The i-FORCE MAX Tacoma and the hybrid Tundra both carry the hybrid battery pack under the rear seat, the spot half-ton installers use to hide a small tank or compressor. The 2025-and-newer hybrid 4Runner raises its cargo floor about 1 to 2 inches to clear the 12-volt auxiliary battery and hybrid hardware, so that cavity is spoken for too.
• The 4Runner has no bed. Every gallon of tank inside a 4Runner is cargo space you lose. A published 2019 4Runner install put the whole system in the spare-tire location, which means the factory spare comes off and does not go back.

Vehicle by vehicle: what the kit pages say

Pulled from current product listings and published customer installs. Prices are the kit only, before labor.

Vehicle	Kit option and price	What it costs you in space
Tacoma, 2016 to 2023	Direct-fit triple-trumpet kit, $1,299.95 list, currently shown as sold out	Tank and compressor under the bed; a 5-gallon tank in the spare-tire location on a published 2016 install, a 2-gallon 17-by-6-inch tank on a 2017
Tacoma, 2024 and newer	No vehicle-specific kit; universal spare-tire-location kit with a 3-gallon tank, $1,034.99	"Requires removal of OEM spare tire from its stock location"; fitment is "universal; some adaptation may be required"
Tundra, 2007 to 2021	Direct-fit kits from $1,199.95	Crossmember in front of the rear axle; about 5 hours for one owner's install
Tundra, 2022 and newer	Direct-fit kit listed but currently sold out; a spare-tire-delete 5-gallon kit on a published 2026 install	Spare tire removed to fit the 5-gallon system under the bed
4Runner, all generations	No vehicle-specific kit; universal 5-gallon packages, or a 2-gallon spare-tire-delete kit as on a published 2019 install	Spare removed, or a tank in the cargo area; compressor draws up to 25 amps

A 5-gallon setup gives 10 to 12 seconds of horn per fill; a 2-gallon tank gives about 5 to 7 seconds with a roughly 50-second refill. Both are fine numbers. The question is whether your Tacoma or 4Runner has anywhere to put the gallons.

What a battery horn gun does instead

A horn gun packages the compressor and the trumpets into one handheld unit that runs on a cordless-tool battery. There is no tank, because the compressor feeds the trumpets directly for as long as you hold the trigger. No tank means nothing to bolt to a composite bed, nothing to squeeze onto the spare crossmember, no 12-volt circuit to tap, and no spare tire to give up.

The 5-Trumpet Horn Gun for Milwaukee® 18V Battery is the loudest version we build: five metal trumpets, output up to 150 dB, a trigger on the grip, and a wireless remote in the box that fires it from up to 160 feet away. It runs on any Milwaukee® M18™ pack, sells for $270 without a battery, and weighs about 4 pounds before the pack goes on. That is less than most of the air tanks in the table above, and it lives behind the seat instead of under the truck.

If your garage runs on a different battery, the same horn gun comes in Dual and Quad versions compatible with DeWalt® 20V MAX™, Ryobi® ONE+™, Makita® LXT™, Bosch® 18V, Ridgid®, Craftsman® V20™, Bauer®, Hart®, Hercules®, and Kobalt® packs. The quad models sit in the middle: four trumpets, the same remote, and a lower price than the 5-trumpet flagship.

A 150 dB horn gun and a 153 dB triple-trumpet kit are in the same loudness class, since it takes roughly a 10 dB change to sound twice as loud, and a healthy 5.0Ah pack delivers north of 1,000 short blasts on a charge.

Where a horn gun rides in a Tacoma, Tundra, or 4Runner

The kit's best argument is that it is always mounted. A horn gun answers that by living in the vehicle rather than under it, and the remote does the rest.

• Tacoma: behind the rear seat or in the bed. Fold the rear seat-back forward and a horn gun with a compact pack lies flat behind it. If the truck wears a cap or a tonneau, the bed keeps it dry and out of sight, and the factory deck-rail cleats give you tie-down points without touching the composite floor. Our guide to hidden no-drill mounting spots walks through both.
• Tundra: cab on the gas trucks, bed toolbox on the hybrid. The hybrid gives its under-seat space to the battery pack, so strap the horn to a bed-rail point or drop it in a toolbox instead. The no-wiring truck mounting guide shows the strap and bracket approaches that need no holes.
• 4Runner: cargo area or roof rack. Strap it to a cargo tie-down with the trumpets toward the hatch glass, or clamp it to a rack basket with the trumpets forward. Either way it is out in seconds at camp, which no under-body kit can say.

Fire it from the driver's seat with the included remote. If the horn lives in the bed and the fob is on your keys, the optional long-range remote reaches up to 2,000 feet.

When the tank kit is still the right call

We sell horn guns, so here is the honest version. Buy the kit if:

• You want onboard air for tires or tools. The direct-fit compressors advertise inflating 37-inch tires, and on a trail rig that is a real reason to carry a tank and a 150 PSI pump.
• You are already deleting the spare. If your Tacoma or 4Runner runs a swing-out or bed-mounted spare, the empty spare-tire location is the one place a tank kit fits cleanly on a mid-size Toyota.
• You are chasing the biggest rating. The stainless triple-trumpet kits list 157.8 dB with a 200 PSI compressor, and a horn gun tops out around 150 dB.

Buy the horn gun if the vehicle is a hybrid, if it is a 4Runner or a 2024-and-newer Tacoma with no direct-fit kit on the market, if you lease or plan to trade, or if you want a train horn without giving up a spare tire, a cargo floor, or a weekend. The half-ton version of this comparison is our F-150, Silverado, and Ram 1500 article, and the conclusion there is the same with more room to work with.

FAQ

Is there a direct-fit train horn kit for the 2024 and newer Tacoma?

Not as of this writing. The main direct-fit lineup stops at the 2023 Tacoma, and the universal spare-tire-location kit is the fallback, with its "some adaptation may be required" note. A horn gun does not depend on a bracket ever being made.

Does a horn gun interfere with the hybrid system on an i-FORCE MAX Tacoma or Tundra?

No. It never connects to the vehicle. The hybrid pack under the rear seat only matters to kit installers who wanted that spot for a tank. The horn gun runs on its own cordless-tool pack, so the truck's 12-volt and hybrid systems are not involved.

Do I lose my spare tire?

No. Spare-tire-delete kits put the air system where the spare was. A horn gun rides in the cab, bed, or cargo area, and the spare stays where the factory put it.

Which battery version do I need for a Toyota?

Whichever cordless-tool battery you already own. The horn gun is built around a battery platform, not a vehicle, so the Milwaukee®-compatible model takes any M18™ pack and the other versions take DeWalt®, Ryobi®, Makita®, and the rest.