I have a 2013 GT 350TS with a single furnace dual zones. This morning I went to turn on the rear to warm up the bedroom and bath....and nothing!! The checked the front and it works fine. So I went again to the back and ran through the other settings to see if it could be a thermostat. All other settings work fine (AC, fan, heat strip). I cleaned out the area around the furnace, which nothing more than a little dust since it was cleaned last Fall. The operating instructions are pretty useless, so I'm stumped. It worked yesterday just fine......