98 windstar A/C problems

My A/C works great in the front of the van. But the rear A/C for passengers only blows hot air. There were even times in the winter when the heater would blow cold air for the rear passengers. Does anyone know what's up and how I can fix it?

The most likely cause of malfunctioning A/C in the rear unit is a problem with the rear air duct deflector. The A/C system is split into two circuits, one for the front and one for the rear. Each circuit contains an evaporator coil and an expansion valve (rear)/orphice(front). Usually the front circuit fails to cool first if the refrigerent is low.

In addition, both the front and rear have an air deflector to direct the blower airflow either through the A/C evaporator coil (cooling) or heater core (heating). These deflectors (on my '96) are powered by vacuum lines controlled on the front dash. The common problem on the Windstar is a failure of the deflector in the rear unit, normally caused by the switch in the dash board.

You may need to remove the plastic panel that covers the rear unit to observe the action of the deflector, or it might be possible to check its operation with a flashlight and some creative use of openings in the panel. If the deflector does not move when you switch the front panel from heat to cool, then you may need to replace the front panel switch.

I had this exact same problem on my 98. Due to a post reply from someone on this site, it turned out to be an easy fix. It was the switch on the dash, the one that controls the rear heat and a/c (turn to left into the blue for a/c and right into the red for heat (I think, or vise versa)). If you search you should be able to find that thread, I listed the part number, price and more details there. I was very thankful for the help from fellow posters and again that it was such an easy fix. It was nice to have the rear a/c working again for sure.

Here is a copy from my last post on that tread:
Thanks again, the switch took care of it. I bought it from the local dealer. Ford part number F68Z-19986-AA, Motorcraft part number YH-1465, paid $38.70, $40.84 with tax. Took fifteen minutes to install; works great now. Thank you