If a gas unit, then looking from the front of Rv at the Radiator , look to the right top of Radiator and your high side is there. On the left side about 12 inches left of Radiator right at the Block expansion valve is the low side. If you still can find it look to the left just in front of the passenger tire and you will see a black box that has two black heater hose and several Air condition hose attach.
