Stop the Blinking Lights! HVAC Calibration for 1996-2000 Chrysler Minivans

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The Problem

The battery on the dogmobile died completely (lost the serpentine belt). After all was fixed, we noticed blinking lights on the console for the heat, vent and air-conditioning.

Some diligent web-searching for something like "Plymouth minivan blinking lights" found several Q-and-A threads and even a couple of videos explaining what was wrong and how to fix it. Alas, only one told the complete story, and that was just a video without any accompanying text. This article provides a printable summary of the procedure.

When all power vanishes, systems lose settings. In our case, both the air-conditioning and the "blend door" controls needed to be recalibrated.

The Solution

Both calibrations can be accomplished by running a built-in diagnostic process just by pressing some buttons, with no special equipment or skill needed.

"905speedgta" has published an excellent video that walks through the process for both, at
https://www.youtube.com/watch?v=eeZBbFGIQ0w

Procedure

For Both Cases

At least one source says the engine must be at normal operating temperature, presumably after running for a few minutes.

The air temperature shouldn’t be too low; if it’s not at least in the mid-40’s, this may not work.

Set the temperature sliders all the way to cold (leftmost).
Set the airflow mode to the panel/vent position (leftmost).
Be sure all the a/c vents are opened.
Turn the blower speed to high.

To Recalibrate AC

console controls

When the lights on the two rightmost buttons (recirculate and AC) are blinking:

Press and hold the lower left (rear wash) and rightmost (AC) buttons until all lights come on and start to blink.

It will cycle through various modes for several minutes.
When done (assuming tests pass) all lights will go out, then the topmost (rear wiper) light will blink. Press it once to acknowledge and it will stop.

To Recalibrate Blend Doors

When the lights on the two topmost (rear wiper and rear intermittent wiper) buttons are blinking:

Press and hold the lower left (rear wash) and topmost (rear wiper) buttons until all lights come on and start to blink.

It will cycle through various modes for several minutes.
When done (assuming tests pass) all lights will go out, then the topmost (rear wiper) light will blink. Press it once to acknowledge and it will stop.

Test Failure

If it doesn’t end as expected, don’t be disappointed. You’ve just learned that something really isn’t working properly and that you need to consult a trained mechanic.