AC blowing out defroster

DaveG39 wrote:
There was a problem on Ford Chassis around that year with an inadequate vacuum reservoir and was a recall years ago to replace the reservoir. If there is insufficient vacuum, the system causes the shutters to close to living area and default to defrosters so you will always have air to windshield. I had that on my 2001 Dolphin years ago.

I don't believe there was ever a "recall" for this problem. I do believe however there was a Ford service bulletin issued. Recalls involve safety items. The heat/AC system is designed to provide windshield coverage in cases where vacuum is lost, so there would be no safety issue.

Service bulletin items are in many cases covered by the factory when the vehicle is under warranty. However I doubt they will still cover something on a 15 year old vehicle.

On the bright side the problem is more often caused by the vacuum line being knocked off the reservoir port when service is performed (or when checking the oil level). The spherical tank should be located in the center of the vehicle right to left, and above the hood opening. You'll probably have to stick your head inside the engine compartment and look up. There should be a small diameter blue hose with a clear fitting that connects to the reservoir.

There is also another vacuum reservoir attached to the frame just below the right headlight. This reservoir has nothing to do with the heater controls, but if the connector has come off or the tank is rusted out the engine may not be able to produce enough vacuum to supply the heater controls. Generally if this tank or connector fails it will turn on the "check engine" light. However I have seen cases where it didn't.