I don't know about adding the sun screen but there should be an on / off switch for the Auto feature on the main control box. Could be located on the top of the box.
I very seldom use this feature unless its very windy or could get that way over night then I might decide to use it. Most time I just leave it off.
05 Southwind 37C
LONG LONESOME HIGHWAY
Going down that long lonesome highway,Bound for the mountains and the plains
Michael Parks / Then Came Bronson - 1969