High idle when air is turned on

Welcome to 2CarPros.

When the AC is turned on, the idle air control valve (IAC) steps the idle speed higher to compensate for the added load. Now, 1500 rpm's is too high. So, what I suggest is this.

First, remove the IAC from the throttle body and inspect the wiring to it and check for carbon or corrosion on the pintle. Also, check and confirm there is no corrosion in the throttle body where it mounts. If all looks good, then try cleaning the throttle body. Make sure there is nothing as far as dirt on the throttle plate.

Here is a link showing how to clean one:

https://www.2carpros.com/articles/throttle-actuator-service

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Here are the directions for replacing the IAC. They explain how to remove and replace the component. I'm adding them to help you locate so you can remove and inspect. The attached pictures correlate with the directions.

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2003 Ford Truck Windstar V6-3.8L VIN 4
Procedures
Vehicle Powertrain Management Fuel Delivery and Air Induction Idle Speed/Throttle Actuator - Electronic Service and Repair Procedures
PROCEDURES
REMOVAL
1. Disconnect the battery ground cable.

pic 1

2. Disconnect the Idle Air Control (IAC) electrical connector.

pic 2

3. Remove the bolts and the IAC valve.
Discard the gasket.

INSTALLATION
1. To install, reverse the removal procedure.

NOTE: Install a new idle air control (IAC) valve gasket.

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Let me know if this helps. Also, let me know if the check engine light is staying on when the engine is running.

Take care,
Joe