Kleinn Bolt-On Train Horn Install — Silverado & Sierra 2500HD/3500HD - GMHD20

Kleinn GMHD20 complete install guide for the 2020–2026 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD — bolt-on train horn kit with onboard air, no drilling required. This is the full step-by-step walkthrough of the Kleinn GMHD20 direct-fit train horn and onboard air system install. We cover every stage from pre-assembly to final horn test — wiring, air routing, mounting brackets, pressure switch setup, and the 1302 tire inflator kit. Whether you're running the GMHD20-230 with the Model 230 Beast Triple Train Horn (153.3 dB) or the GMHD20-734 with the Model 730 Demon Triple Train Horn (157.8 dB), this guide covers the full process. What's in the GMHD20 kit: Triple train horns (Model 230 Beast or Model 730 Demon — depending on variant) Kleinn 6350RC or 6450RC fully waterproof air compressor — 100% duty-cycle 2.6-gallon air tank Vehicle-specific powder-coated mounting brackets Wiring harness, relay, and pressure switch 1302 tire inflator kit All hardware and airline fittings Kleinn is the only brand building a fully waterproof automotive air compressor. The GMHD20 is a 100% bolt-on system — vehicle-specific brackets, no drilling required for most installs. Shop the GMHD20 Kit → https://kleinn.com/products/direct-fi... If this install helped you out, subscribe to the Kleinn channel for more direct-fit air horn and onboard air system content. Drop your truck year and build in the comments — we want to see what you're working with.