QuestionQUESTION: The blower motor for the AC/heater runs on high all the time. The only way to shut it off is to pull fuse or unplug motor. The controls on dash are push button with digital readout. I replaced the module (Chrysler part # 4596060) located behind glove box on passenger side, in ductwork, it has two sets of wires going to it...One for the blower and the other is a four or five wire plug. The module replacement didn't help, still runs all the time.
ANSWER: Hi Richard,
I would have hoped that the module would cure the problem.
You have a couple of possibilities:
Check that the red/light green wire at the module is connected to pin 4 of the black plug of the body control module (on the passenger cowl panel under the trim panel) which is the fan speed control signal wire. But I would check the continuity of that wire by piercing thru the insulation with a pin rather than pulling the plug at the body control module end which may otherwise cause havoc with the theft system if you pull the plug out. I suspect that the wire is grounded (which would make the fan run at high speed all the time) and it could be that there is some crud on the black plug socket/pin interface or a short in the wire itself. To check that you may have to pull the plug. But if you find the engine won't start and run for more than a few seconds that means the theft system interpreted pulling the plug as an attempt to steal the car.
So then you would lock/unlock either front door to clear that snafu.
Then it could either be the body control module or the ATC head unit is bad. You can check the head unit by doing a self-diagnostic test. Here is how I described that for another owner:
"The "computer" is a part of that control panel in the dash. Before concluding a new panel is needed a test should be done to see if the computer has recognized any problems and described them in the form of two digit fault codes stored in its memory. Did someone do such a inquiry? If so, what numbers did they get? If not you can do the readout yourself:
The unit does have a self-diagnostic capability. The engine has to be running and the car not in motion to do the test. Simultaneously press the floor, mix, and defrost buttons, (the 1st,2nd and 4th on the top row) and see if the display unit begins to blink. Release the buttons when it has started to do that and then after it blinks for a while longer watch for two digit numbers to appear on the readout. Those are the fault codes. If the first number appears and stays in place, push on the first button in the bottom row (panel) to continue the readout. At the end of the readout the unit will return to normal settings.
Then write back with the number(s) and also tell me more about exactly what is wrong with the function of the unit.*
If the head unit doesn't respond at all, then check fuse #6 under the dash. There is also a 12V supply line to the control that is directly connected to the battery on a black/pink wire on the green plug on the rear of the control unit that should be checked to verify that you are getting that power to the control unit.
I would do a thorough readout before buying a new control unit. And you also might find a working used unit at a wrecking yard.
Roland
*The code numbers range from 23-36. You can also get a decoder list at www.allpar.com/fix/codes_climate.html"
The last possibility is the body controller, but that you would want to check out using the Chrysler Diagnostic Readout Box II at a dealer, unless you can find one at a wrecking yard.
Please let me know what you learn. The system is mediated by the digital data bus from the ATC head unit, to the body computer, and then by a variable resistance presented to the blower motor by that wire on pin 4. So that has several possible reasons why you have lost control.
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QUESTION: Roland, I checked the red/green wire at module, it was ok. The ATC head unit was dead. There was no readout on the digital readout, so I couldn't run the self-diagnostic test. I also checked the fuse #6 under the dash and the 12 volt supply line to the control that was connected with black/pink wire to the green plug on the rear of the control unit, and it was okay. Then I pecked on the ATC head unit with the plastic end of a screwdriver, and it started working. I don't know if it was a stuck button on the control head or a short in the unit? What do you think? But for now it's working fine. Thanks, Richard
AnswerHi Richard,
I appreciate that information and noticing the several power wires to the control unit, some of which I hadn't noted. It may be a cracked solder joint on a connection between the plug socket and the circuit board. That would be the sort of thing that responds to mechanical flexing. At least you know what to look for and ideally it won't require buying any other module.
Roland
