If possible safely, check the connectors for the lines going to the D11's. They may need replaced or pushed onto the cable further. Changes in temperature also affect connectors. Good luck...
repeat satellite setup...at satellite setup screen change tuners from dual to single...that should remove the channel for the 2nd tuner from the swm lnb, allowing to add another channel...hope this helps...good luck
locate the 13v 101 line coming into the multi switch and test the signal on that line, if there is no signal check that port at the lnb. my guess is the lnb is bad, but it could be the cable or connector...good luck