I do not ever recall seeing this question!
Be forewarned though, the base diagnostic trouble code (DTC) descriptions are very short & cryptic.
But it's a good start to identifying the components/sensors/readings that are involved.
See "Related Links" below for 2 sources of Ford OBD codes listings...
The "Related Questions" below cover the Check Engine Light and retrieving the diagnostic trouble codes (DTC).Lots of detailed information and guidance...
get an engine diagnostic check, a lot of different problems can contribute to your situation.
If your check engine light is blinking with the engine running that means an engine cylinder misfire has been detected . You will need to have your Ford Windstar scanned for any trouble codes to help diagnose and then repair the problem . You can drive it in to have it repaired , just drive in a moderate fashion ( avoid any rapid acceleration or deceleration because you can damage the catalytic converter )
The "Check Engine" light is a diagnostic indicator showing that the On Board Diagnostic computer has detected a problem and has saved the trouble code. You can get the trouble code from the OBD system using a special computer attachment. Most auto parts stores will get the trouble code for you for free (and be happy to sell you the part that would need to be replaced.) Check the trouble code to insure that it is referring to a flow issue. If the electrical system is at fault, consult your service manual for the proper test.
Apparently, turning on the air conditioning is triggering the computer to send a DTC (diagnostic trouble code) to the check engine light. It would be in your best interest to have the OBDII connector scanned and retrieve the trouble code(s) to find what is causing the check engine light to come on.
Trouble code P1537 means: Intake Manifold Runner Control Malfunction (Bank 1 Stuck Open)
One context that I have seen this "CKT" reference is in relation to a diagnostic trouble code (DTC) - specifically relating to the vehicle speed sensor.CKT is an abbreviation for an electrical circuitIf the CKT in question is part of check engine light trouble code, the only way to research the causes of those codes is to use the basic DTC code and not just CKT.See "Related Questions" below for more
The Check Engine Light (CEL) will be on - there are diagnostic trouble codes (DTC) very specific to problems with the O2 sensor that indicate a failing sensor. Most times though, the DTC indicate other problems dur to the readings coming from the 02 sensors. See "Related Questions" below for more
There must be a "check engine" light on. Start with investigating the DTC's (Diagnostic Trouble Codes).
The most common engine check engine light codes would be indicating that something has gone wrong under the bonnet basically. Each manufacturer has different codes and so the garage uses diagnostic computer tools to find out the problem.
a human brain is the best.
The key here is that each warning light is trying to tell you 2 different things. They are not likely to be related to each other.Research each light separately.NOTE: Fix the *cause* of the trouble codes and the lights will turn themselves off.See "Related Questions" below for more about check engine lights & Windstar ABS systems