Ok,, I took a very close look at that plate's rear
Now I"m visiting a web site, be right back
Ok back now,, In this photo there are no 12 volt wires hooked up you can call the 3 connections 1 2 and 3..
The park cable is #2, the one in the middle
#1, I believe is the roof and #3 is TV-TWO
If your plate is the same as this one (Winegard) then you have nothing connected to the park cable in connection.