* Low Refrigerant (AC only): If it's not blowing cold air, this is the most likely culprit. A leak in the system requires a recharge by a professional. Don't attempt to recharge it yourself as improper handling can be dangerous.
* Blown Fuse or Relay: Check your owner's manual to locate the fuses and relays related to the HVAC system. A blown fuse or failed relay can cut power to the blower motor or compressor.
* Blower Motor Resistor: This component controls the fan speeds. A faulty resistor can cause the fan to not work at all or only operate at one speed (usually high).
* Blower Motor: The blower motor itself might have failed. This is a common point of failure in older vehicles.
* HVAC Blend Door Actuator: While you say the doors controlling airflow direction work, a problem with the *actuator* that controls the temperature blend (hot/cold mix) could prevent air from coming out altogether. It might be stuck in a position that blocks airflow.
* Frozen Evaporator Core (AC only): If you've recently used the AC extensively, and there's a refrigerant leak, ice can build up and restrict airflow.
* Vacuum Leaks (For Vacuum-Controlled Systems): Older Windstars might use vacuum to control some HVAC functions. Leaks in the vacuum lines can prevent proper operation.
* Defective Blower Motor Switch: While less likely if the door actuators work, the switch itself might be faulty.
Troubleshooting Steps:
1. Check the Fuses and Relays: This is the easiest and quickest first step.
2. Listen Carefully: Turn the system on. Can you hear *any* noise from the blower motor (a whirring or humming sound)? If not, the motor or its resistor is a likely suspect.
3. Check for Obstructions: Make sure nothing is blocking the vents or air intakes.
4. Consult your Owner's Manual: Find the diagrams for the HVAC system and fuse box.
Recommendation:
Since diagnosing and repairing HVAC problems often requires specialized tools and knowledge, it's best to take your Windstar to a qualified mechanic, especially if you're not comfortable working on your car's systems. They can properly diagnose the issue and perform the necessary repairs. Ignoring the problem can lead to more extensive (and costly) damage.
