2003 windstar rear heat not working

[2k3windstar]

Rear heat recently stopped working. Symptoms: With rear temp control on heat, air comes out bottom vents, fan works at all speeds, but cold air comes out. Switching temp to cool moves air flow to ceiling vents, and provides refrigerated air. Symptoms the same if using dash controls or rear controls. Rear heater hoses under car are warm. Front heat/ac works normally. Coolant level is normal. Have not checked any fuses yet (no flames please).

Other info: My wife recently bumped a guard rail with the right front fender, avoiding another vehicle. No injuries, and car is driveable. Car scheduled for repair in Jan. Rear heat has worked since accident. I protected the headlight wiring with duct tape to keep it from rubbing against the bent fender. Headlights function, replaced turn signal bulb on right side. Don't think it is related. If it is, I need to add it to the insurance claim.

Troubleshooting: Removed rear panel, heat blend door actuator was in the cool position and did not move in response to temperature selector. Blend door would move freely with actuator removed. I opened the actuator and found a small electric motor, and a circuit board with a slide "potentiometer" for position feedback. I tested the unit by putting 12VDC on motor. The actuator would move freely in both directions. Cleaned a little residual grease from the potentiometer pads, manually put the actuator half way between hot and cold, and put it back together. With the actuator plugged in, but not mounted to the door, the actuator would not move towards the hot position with temp in hot, but did move to cold position with temp in cold. Tried this with both front and rear controls. Same result.

At this point I figure either the motor is not being commanded to go to heat (computer?), or the position feedback makes everything think it is already at heat (actuator?). The temp control moves the air from floor to roof, so that appears to be working. Any ideas? I know the car is still under warranty, and I could just take it to the dealership and let them fix it. All of my past experiences (from recent to several years ago) with the local dealer make me want to do that as a last result. If it is relatively cheap, I'd rather just fix it myself. And now that I've opened the actuator, it will automatically be bad. Any suggestions on sources of technical info?

Here in South Alabama, rear heat is a luxury, not a necessity. Rear AC is a necessity, and its working. I can take some time to work this out myself.

Oh, and I previously owned a '95 Windstar, 3.8 Liter. Experienced almost all of the common problems. My manuals are more suited to that year than to 2003. Thanks.

[12Ounce]

Have you tried swapping the two rear actuators? ... just as a test. They are the same part number.

[2k3windstar]

That would have been a good test. But, no, I did not try swapping the actuators. The actuator that switches the air from floor to ceiling sure looked different. It has an arm on it that moves the damper. The heater damper actuator had a shaft that went straight into the damper. Seeing the physical difference, I did not even bother looking at the part numbers. Now that you say they are the same, I wonder if the arm I saw slides on / off the shaft of the floor to ceiling actuator?

The P/N on the heater door actuator is XF2H-19E616-DC.

[12Ounce]

I don't remember that detail. My point of reference is a '99... so I may be misleading you. But it would surprised me if Ford change one of the actuators to something unique.

[Drewan35]

Originally Posted by 12Ounce

I don't remember that detail. My point of reference is a '99... so I may be misleading you. But it would surprised me if Ford change one of the actuators to something unique.

Was at the dealer yesterday they told me that the actuator for the rear is a different part number from the front. That is on a 1999 ford windstar.

I have a similar problem with the rear heat everything is working fine minus the heat. But I don't hear any unusual noises. It just will not blow hot air. Does anyone think this could be the actuator in the back that has gone bell up? The rear has been out for almost two years, never really felt the need to look too far into it. But if it is as easy to fix as the front I would like to fix it. If you have any help it would be most appreciated.
I have checked the anti-freeze level, It's normal. The line's leading to the back are heating up, feels very warm.

[12Ounce]

Drewan35
Now ya got me wondering! I've always assumed the front and rear (two) actuators were the same part numbers because they look so similar.... but the dealer would know...or should know.