Dryer runs but no heat. I checked for continuity at heater element, ect. everything checked good but thermal protector. I checked the blower its tight and clean as is the vent and all associated duct work. Vent flap on outside of house also free and clean. I ordered a thermal protector kit and installed the protector, and dryer worked fine for 3 loads then stopped heating again. Thermal protector is open again. I took heating element off and took it apart, everything looked good, does not look like its grounding to housing. I reassembled and checked continuity again both the element it self then one contact on element to housing checked good. I'm at a lose Please Help!