LX 665 New Holland heater fan works but no heat. Radiator is full, unit gets warm but I don't think it is circulating through the heater core (unit has factory heat and ROPS, glass, etc.) What should be checked first? Any fuse or relays or is it only a manual lever/switch? Need some help fast as a storm is approaching and I use it for snow removal. Can't locate my manual. I'm batting zero and now I'm in the 2-minute drill! Thank you.