The air horn that comes with Mecedes Benz Sprinter is not very loud. It's not easily heard by others in time of neede So Agile Off Road put together a great combination of frequencies to enhance the air horn. It's a very simple upgrade to swap out the air horn. Agile Off Road provides an excellent instruction on how to do this upgrade. It involves removing the front grill which is help in place by 3 screws and snaps. Then mount the enclosed bracket onto the front center bracket and then 2 wires to patch.

Agile Off Road 2019 Sprinter horn upgrade

https://agileoffroad.com/product/agile-horn-kit-sprinter-2019/

* the link above is not affiliated with me