Thanks the reply, found the problem, bottom of box holding water heater has a swing down panel at rear which had only 1 of 3 screws securing in place leaving about 1/4" of room for a dang mouse to get in, chew thru the Styrofoam, climb up on top and build herself a nice little nest. As part of the nesting process all 4 wires needed to be removed, unbelievable, every wire was broken and 3 of them in 2 places. All fixed and good now, thanks,,,MARK