2004 Freestar, MIL's car...


The AC works, but the driver side air temp is noticeably less cool than the passenger side. I suspect a blend door issue of some sort, but am not familiar with the workings of this cars bits and pieces. I had also read that the refrigerant being low could cause this issue. Where do I start?

 

There's not a lot of Freestar expertise here, but some basic principals may apply.

Get a thermometer that you can stick into each air register to take measurements and compare. Usually, the center 2 will get the coldest, as they get the highest volumes of air more directly from the air box. The passenger and driver's side are further away, their air flow will be lower, so they may take a while to cool down, and may not cool down to the same levels as the center on a hot day.

Run the AC at high setting with the engine idling. If the refrigerant is low, the compressor will tend to cycle on and off frequently with the idling engine. The best test is to attach some gauges and check the high and low side pressures, and compare against specifications. Follow instructions on the gauge set on using them.

If the air box is like the Aerostar's, the fan is attached from the front. If so, remove the fan to see if the is any debris in there clogging the AC evaporator. If so, clean out as much as you can; use a vacuum cleaner to suck out anything stuck in the evaporator.

Checking the blend door will require taking apart the inside air box, and can get very involved. Find a service manual for the van and read up, if you want to do this.