The battery or computer were disconnected and the system has to be reprogrammed. That will not work if the AC system isn't working. Here's a page from my web site:
Reprogramming the Chrysler HVAC Computer
Automotive heating systems used to work fine with slide levers and push buttons but today the designers have convinced us it's important to be able to blow air from three or four different places at once. That means use of an insanely complicated computer module is necessary to provide all of these features. Due to production tolerances and variations, the engineers built in two self-calibration features. Once the sensor values are learned, the computer stores them in its internal memory and uses them to determine where to position the various mode and temperature doors. That memory is lost when the battery is disconnected or run dead. When reprogramming is necessary, the six yellow led lights in the switches will be flashing. Those values must be relearned by initiating these two procedures:
Actuator Calibration Test
1. Set blower motor on High.
2. Set Mode position to Panel.
3. Open all AC outlets.
4. Set temperature to cold.
5. Press Wash and Rear Wiper buttons at the
same time for five seconds until all leds flash.
5. All leds will turn on for five seconds.
6. The calibration test is running when the Rear
Wiper and Intermittent leds are flashing
alternately.
7. Acceptable result is the Rear Wiper led is the
only one flashing. Press Rear Wiper to exit. At
this point, the calibration and cool-down
procedures can be run separately.
Cool-Down Test
1. Set the blower motor on High.
2. Set mode to Panel.
3. Open all AC outlets.
4. Set the temperature to cold. (See note 1 at the
end).
5. Press Wash and AC at the same time. (See
note 2 at the end).
6. All leds will turn on for five seconds.
7. Cool-down test is running when AC and
Recirc. Leds are flashing alternately. If they
flash at the same time, the test has failed.
8. To abort the test, press the Rear Defogger,
Recirc, and Rear Wiper buttons or cycle the
ignition switch off and back on.
9. The manual doesn't say what to do next, but
as I recall, if the test passes, only the AC led
will be flashing. Press it to exit the procedure.
Note 1: Then there's a note in the manual that says the test will fail if the ac evaporator is already cold. HUH? "To
correct, operate system with AC OFF and the blower motor on high for three minutes prior to starting the
test". That's probably why I remember putting the temperature to hot before starting this test.
Note 2: For the Cooldown test, the manual say to "Press Wash and AC at the same time". Later, it says "Cool-
down test is running when AC and Recirc leds are flashing alternately". To start the test, I think they meant
press the AC and Recirc buttons, not the AC and Wash buttons. Try it both ways if you have to.
The cool-down test is confusing at best. I had the best success by running the air conditioning for a few minutes before starting the procedure, and placing the temperature control on HOT. As soon as the two leds start flashing alternately, move the control immediately to COLD. The computer is looking for an 80 degree temperature drop within 20 seconds at the in-car temperature sensor. This is usually pretty easily accomplished as long as the AC is working. Typical duct temperature under full heat is over 140 degrees, and ideal temperature under full AC / cold should be around 40 degrees. If multiple attempts to pass this procedure fail, try repeating it immediately after a ten minute drive at highway speeds. These radiators are so efficient that they may reduce engine coolant temperature too low even without the electric radiator fan turning on. Driving on the highway will bring the engine temperature up for a higher starting point.
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Tuesday, March 19th, 2013 AT 3:03 AM
