Questions and Answers
Chrysler Cirrus Heater Controls
Q. 1996 Chrysler Cirrus heater problem. When I move the heater control module knob to the various positions the air does not come out of the correct vents. The major one I am having a problem with is the air being directed out of the top front window defrost vent. No defrost at all.
The Haynes Manual says to check the module for resistance along terminals 5 and 8 and if the resistance is not correct when the knob is turned to the various settings to replace the module. So what are they saying? That the various electrical outputs from the module controls the position of the vents flaps that moved mechanically in the past?
I tried to look behind the dashboard trim but was unable to see anything without disassembling further. So is it correct that I need a module that gives the correct resistance reading for the various positions or it just won't work. What happened to good old levers and cables?
Any help would be appreciated.
Bruce
Vancouver B.C.A. In a nutshell, yes. The mode switching is done by a small electric motor.
The mode door actuator is an electric motor. It mechanically positions the A/C unit panel/bi-level door and the floor/defrost door. Prior to part replacement, re-calibration of the HVAC actuator is recommended.
Calibration is performed by disconnecting the battery negative cable or the removal of the instrument panel M-1 fuse. Electrical power should be re-established after (60) seconds which will automatically initiate the software calibration procedure.
If this procedure fails, it will be necessary to replace the mode door actuator/motor. The mode door actuator/motor is not serviceable and must be replaced if found to be defective.
To test the control panel:
- Remove the control switch from console and disconnect control switch (Fig. 2).
- Using a ohmmeter, check leads between Pins 5 and 8 of the 8-Way connector. Turn the control module to each position shown on chart below. The resistance reading should be within the specifications shown.
Switch Position Ohm Range Panel 828 to 856 ohms Bi-Level 1.279k to 1.315k ohms Floor 2.302k to 2.358k ohms Mix 5.202k to 5.318k ohms Defrost 99.5k to 101.5k ohms If not OK, replace the control module. If OK, check:
- Blown fuse
- Cut wire
- Poor ground
- Poor connection
- Defective BCM
- Bulkhead connector inoperative
What happened to good old levers and cables? There isn't an auto maker in the world who believes in the K.I.S.S. principle anymore.
Additional Information provided courtesy of AllDATA