Goto network and autoconfigue with all sources on including trolling motor and then you may need to turn some files on lowrance and motorguide customer service is second to none give them a call. Be sure your units have the most up to date software BEFORE calling though most of the time that clears issues up.
Do yo already have the Lss2 structure scan transducer Dirty?
Might be worth throwing a bid in?
http://www.ebay.com/itm/Lowrance-HD...412056?hash=item4afaafe7d8:g:Iz0AAOSwP~tW36fr