Our thermostat had been going blank and then coming back on for a while. We installed new thermostat and still cannot get unit to run. Called Honeywell customer service and all is connected correctly. We touched red and green wires together and got no response. Wondered about the fuse. Where would it be located on a Rheem heat pump? Is the transformer on the heat pump unit outside or in the unit in the attic? Not sure if it makes a difference, but ours has axillary heat. I want to check this before I pay for someone else $125 to replace a $1 part!