Unit tucked away in a very tight closet. Had to dig lots of things out of closet in order to access unit, air mattress, comforter, paper towel rolls, pillows, and toilet paper rolls Inspected unit and found mouse nest inside of heating element compartment. Mouse was hanging from element hookups and short circuiting unit. Remove mouse and test run system. Vacuum nest debris to deter future nesting. Comforter in closet seemed to be a source for nest I would recommend trashing it and sealing any openings on room allowing mice in.