The old goo has to go, and since it is silicone, cleaned thoroughly to remoive the oily residue so anything else can stick. A cloth dampened with mineral spirits usually works (just dampened - do not soak the area with any kind of solvent).
The Eternabond tape is an excellent choice, but you could also use a white lap sealant to close that slit or tear. Dicor makes one,but avoid the "self-leveling" type, since it will run on a vertical surface. You want the "Non-sag" formula, which is Dicor 551-LSW for the white color.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL