I have an '80 Elky non a/c. New radiator and thermostat. Both hoses to the heater core are hot so water must be flowing through it, but I can't get any heat in the cabin. I pulled the glove box off and looked at the cables and one or two appear to not be working. I flipped the doors manually back and forth but still got no heat. The fan works and blows air, but just feels like ambient air temp. Which door and cable lets the heat in? I want to make sure I'm flipping the right door before I open it all up and check for an uninvited guest in my heater core box.