Nothing is broken. Nothing is dangerous. But...
Any time a brand-new vehicle hits the market there are bound to be some first model year issues. The Ford Bronco is no exception. The good news is that none of these issues are serious, like poor hardtop build quality and paint wear on the roll bar. They're not dangerous and don't affect vehicle safety or anything mechanical. Still, they're a nuisance for owners. And now there appears to be yet another one, though only certain trim levels seem to be affected.
Some members of the Bronco6G forum have posted complaints about hearing an annoying whistle sound coming from the grille and hood section. This only seems to afflict the Big Bend and Outer Banks trims. Fortunately, Ford is fully aware of the problem and it's already taking action.
One forum member posted the Technical Service Bulletin (TSB) the Blue Oval very recently issued detailing specifically what needs to be done. Ford says some of these specific Bronco trims "may exhibit a whistling noise originating from the front of the hood area when traveling at speeds above 30 mph. If the whistle noise can be eliminated by taping off the gap between the hood and the grille opening, this condition may be dueto the hood seal design. Hood seal replacement will not resolve this condition."
In other words, there's airflow coming through due to a gap between the hood and grille. These trims' front grille design differs from other Bronco trims.
However, not all owners are satisfied by the TSB because it doesn't address another whistling sound they're convinced is coming from the driver-side mirror. In all likelihood, Ford has not yet discovered a gap or gaps in the mirror housing. One owner's temporary solution was to cover the gap with electrical tape. Others figured out a fix by placing their hand in front of the mirror or by slightly turning it.
Of course, all of this is temporary and it's up to Ford to fully resolve things. For now, there's just one whistling-related TSB for the hood and hopefully, a second one addressing the side mirror is forthcoming.