Those who have perused the order guides of the 2017 GMC Acadia and 2017 Cadillac XT5 may have noticed a line called “horn, dual note” with reference RPO code U05. The feature piqued our attention, so we asked GM what the feature is all about.
As it turns out, the dual-note or dual-tone horn is essentially two tones sounding at the same time, making the horn itself louder.
GMC tells us that the each one of its vehicles is equipped with the dual-note horn, but examining GM’s order guides only shows it being on the first- and second-gen GMC Acadia, 2017 Cadillac XT5, as well as the Chevrolet Traverse. Interestingly, it’s not present in the order guide for the Buick Enclave, which shares the Lambda platform and much of everything else with the first-gen Acadia and Chevy Traverse.