Rear A/C not working

[00pathySE]

Front a/c works good. Rear blows outside air, but blows hot when set to hot. Can someone explain how this works exactly? Are there two different a/c systems (front and rear)? How does the front ac work fine while the rear doesn't? Is there a separate fill port for the rear ac refrigerant? Any insight would be appreciated. Thanks

[smj999smj]

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.

[00pathySE]

OK thanks for the info. I plan on pulling the panel off and having a look.

[00pathySE]

I pulled the panel off. The actuator seems to be working fine. I can watch the motor move and temp changes with the temp control knob. But no ac to the rear. The ac lines are not warm or cold either near the rear unit. If they have been blocked off, where would the dealer have blocked them off? Any suggestions would be appreciated. Thanks.

[smj999smj]

The only reason they would be blocked off is if the lines were leaking, which did occur on these vehicles and cutting the rear lines and capping them off was one way they were "fixed." For awhile, the only repair Nissan offered was to replace the entire rear A/C and coolant line assembly that ran along the frame rail, which usually involved raising the right side of the body off of the frame slightly. If the leak is accessible and the rest of the lines were in descent shape, a section of the aluminum line could be replaced to repair the line. Companies like Dorman make repair kits for aluminum lines. If your lines are capped off, then it shouldn't be too hard to find. You'll have to trace the lines back to the engine compartment and find where they were capped off.

[00pathySE]

Thanks! I'm going to leave it for now. Maybe a project for down the road.