Help, rear wiper problem!

[Mike_oat]

I just changed the rear wiper arm on my 2009 Tahoe LT. Now when I first turn my wiper on, it turns to far causing the wiper to go down onto my tailgate, almost all the way to my license plate, but it’s only happening when I first turn it on, the second turn it is back to normal. If I shut the rear wiper off and then turn it back on again, then it also does the same thing on the first turn. It’s going to far and I thought maybe I needed to adjust the wiper arm, but that’s not the case. Is my wiper motor bad?

Thanks in advance