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Chrysler Repair/ATC not working in Chrysler '00 300M


QUESTION: Hi there:  
I have my car in the shop and am afraid they are trying to fix it by find the bad part method. They originally told me that it needed
an Expansion valve, dryer and pressure switch.  Now they say ANOTHER switch (I have no idea) won't let the compressor come on, and whatever that is is a special order from Chrysler. I know this sounds vague, but I took it in, and it was simply not blowing "cold" air. I think the switch is the dash control, and I also believe this thing can be reset. Aren't you supposed to bring the temp to high for 5 minutes, then bring it back to where you want to set it?
At this point the car has been at their shop for three days, and it's not fixed. I about am ready to pick it up, because I don't believe they've taken ownership of the problem and tried to fix it in a timely manner. I got the "we've been really busy story."  This after making arrangements in advance to take it to the shop. I was told yeterday morning they needed to order the latest part, and found out at closing time yesterday they hadn't even bothered to do that.  They also drove it to try to make the compressor come on. Is this necessary in this particular car?
Please help.

ANSWER: Hi Rowen,
If the issue is that the compressor won't activate even though the refrigerant in the system is at the proper level then the issue could be fuse B (in the power box in the engine compartment), fuse 21 in the fuse box at the left end of the dash), the compressor clutch relay (power box), the clutch proper at the compressor, the pressure sensor being inaccurate, or engine controller/body controller not supervising that circuit as they should. The body control module communicates with the Heater/AC control panel, and then the bcm communicates to the engine controller.
There is thus a 'chain' of connections involved but with the on-board self-diagnostic properties of the system it should be straight forwand to identify where the problem resides.
If they can't fix it promptly and without 'throwing parts' at it, then I would get the car back and ask them to put back anything they removed and not charge you anything.
If the compressor works but you don't get cold air, then there is a self-diagnostic capability of the control panel/HVAC distribution box under the dash.
Let me know what you lear, and if you write back tell me if this is a conventional aor a digital readout type of control panel.
Please 'rate' my answer (see below).

---------- FOLLOW-UP ----------

QUESTION: They've now admitted they mis diagnosed it, and said I won't be charged for all those parts, and he's saying it is the dash controller.
I've demanded it be returned to me tomorrow early afternoon, fixed or not.
Afraid I wasn't very nice on the phone.
It's digital.

If it is the controller then they can run a self-diagnostic test to see what it thinks is wrong with itself. Turn the engine on, set the temp at 75>sno F, then simultaneously press the lower 4th button, the upper 5th button, the upper 6th button (floor, mix, defrost) and the control display should start to blink, then release the buttons and wait till the blinking stops to see of any 2-digit numbers show up on the display. If so, note it, and then press and release the upper 4th button to see any additional codes. Let me know the results.
You can fix some of these codes yourself with info from the manual. Thanks for the rating/nomination.

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Roland Finston


Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

I answer questions seven days a week and respond to you in about 30 minutes. "Maxed Out" means I am answering another question, briefly unavailable, so try again later.

I have do-it-yourself experience (50+ years) and a library of 100 1982-2012 Chrysler factory shop manuals and 20 multi-manual Chrysler Corp. CD's.

I was voted "Top Expert" 2010-2015, here at AllExperts, and have answered 20,000+ questions.


Five decades as a 'do-it-yourselfer' on domestic and imported cars.

Yahoo Autos Group called The Chrysler Lebaron Club (co-moderator)

Advanced degrees in Physics/bruised knuckles

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"Top expert" of 2010, 2011, 2012, 2013, 2014 and 2015 here at Allexperts. Quickest "average response time" at Allexperts (currently no. 1).

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