Im having the same issue with my 2008 launch 21v.The gauge will stop at 50% but the digital screen will go to 100%. So i'm not sure if it's really only going down 50% or what. It didnt seem to completely plane out but that could have been just in my head seeing that the gauge wasn't working. Jenvey, how do you re-calibrate it? I checked the connection and and it seemed fine. I'll need to dig into this more this spring when the boat is out of storage.