Air Conditioning, 1995 Grand Caravan

[4breezes]

This is a 1995 Grand Caravan with a 3.3 engine.

Several years ago the A/C quit while my wife had the car in Maine. She took it to a repair shop (dealer?), and was told that the problem was in the rear A/C unit, behind the quarter panel just behind the driver's seat, that this was a very common problem, a common failure, and that it would cost $350 to fix. They also said that the entire A/C system was non-operative until the rear unit was fixed. She said something rude and left.

Now, with summer coming, and promising to be hot, I'm looking at the A/C. It certainly needs more than a simple recharge. It doesn't work. Actually, I'm not sure I can say that. Since it broke I haven't really tried to make it work. My recollection is that it doesn't work in any way.

I started looking today. The coolant lines are in place and seem undamaged. The controls for the rear unit have two functions, A/C or heat, and fan speed. The fan control is dead. Nothing happens at any of the fan speeds. When I switch between A/C and heat I can hear a very faint humming/whirring for four or five seconds, as though the unit is changing a door/flap in the ducting. These simple tests were done with the ignition on, engine off.

What is it in the rear unit which disables the entire A/C system? Where do I start?

Covering all bases, this is posted on another site also.

As always, help and suggestions appreciated.

[RIP]

I'm more familiar with generation 3 (96-00) van ventilation systems so this may or may not apply. A mode door in the rear A/C heater unit (on the pass side rear on gen 3 vans) diverts either cool or hot air into the cabin. You are probably hearing the mode door motor positioning the door. Probably safe to say that is not your problem though there is the small posibility the shaft has separated from the door.

As far as I know the front and rear systems are independant from each other except they both use the same condensor mounted in front of the radiator. Not sure why they are saying the rear has to be fixed for both to work. Maybe that's a difference between 2nd and 3rd gen vans.