Mountain Dew A.M. was a Mountain Dew flavor (alternatively named albeit "Orange" in Applebee's restaurants a few years later.) exclusively available in soda fountain machines only at Taco Bell restaurants before its discontinuation. It was re-released in Applebee's a few years later, but was likewise discontinued shortly thereafter.
Mountain Dew A.M. was a blend of PepsiCo's Tropicana Orange Juice and Regular Dew together. In technical terms, it should have about 50% Tropicana Orange Juice and 50% regular Dew together. If that is not the case, the Mountain Dew to orange juice ratio depends by location. It is similar in both concept and flavor to another discontinued blended drink, Orange Mango Dew from Taco John's. Its color had a greenish-orange look.
Its Applebee's release describes it as "Ice Cold Mountain Dew with Orange Juice."
2012 - 2013 Taco Bell release
Mountain Dew A.M. was first released in September 2012 as part of Taco Bell's new breakfast main menu. Shortly thereafter, in early 2013, the flavor was discontinued for unknown reasons.
2015 - 2016 Applebee's release
Mountain Dew A.M. (now called "Orange") was released in 2015 at Applebee's as part of their main menu. A year after its release, it was removed from their online menu, making it presumably discontinued.