Postby smj999smj » Sat Jun 04, 2016 4:49 pm
The rear system is a separate system as far as having a separate cooling and heating unit, but it uses the same refrigerant. The rear system has lines that run up to the engine compartment and feed into the lines of the front system. The rear system has it's own expansion valve, evaporator core, heater core and mode door actuators. If the front system is cold but the rear blows warm or hot (when set to the "cold" setting), I would be thinking there might be a bad mode door actuator for the air mix door at the rear heating and cooling unit. Of course, it could be a wiring or control head issue, but failing actuators are much more common. The rear unit is located behind the right side, rear interior panel, which has to be removed to access the unit. I'm not sure where the actuator is located on the unit, so, I'm not sure if the unit will have to be removed to replace the actuator or if there is room to replace it without removing the unit.