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.