1998 Chrysler Concorde Auto Temp Control

Hello - just a couple of things you might check/try. First read the info on ATC In-Car Temperature Sensor and Ambient Air Temperature Sensor. Me I would first do the check on the sensor motor fan, I have attached that. I don't believe it is the thermistor in the ATC only because it says it should be throwing a code. You said the dealer/shops don't see a code. I would next, go ahead and replace the Ambient Air Temperature Sensor (I have attached the pics where it is) mainly because if the sensor motor fan inside the car is working after the test, the thermistor appears to be working (no codes) the Ambient Air Temperature Sensor ". . .is used by the ATC system to adjust blower speed, temperature offsets, evaporator temperatures and mode control." This seems more like what you are saying. Plus it is only about $17.00 by my info at the dealer, part number 4688204. You might check Auto Zone, O'Reilly's etc also. Good luck and be safe.

ATC In-Car Temperature Sensor
The Automatic Temperature Control (ATC In-Car Temperature Sensor returns electrical signals to the Body Control Module (BCM). The In-Car Temperature Sensor is used on ATC equipped vehicles only. The In-Car Temperature Sensor is made up of two parts. One part is the in-car sensor motor fan assembly and the second part is a temperature thermistor. The in-car sensor motor fan assembly attaches to the back of the ATC Control head. This assembly has a small fan and a motor which draws air through the intake on the front of the ATC control. The in-car sensor thermistor is located inside of the ATC Control Head. Air drawn from the passenger compartment by the in-car sensor motor-fan assembly, flows over the thermistor. The in-car sensor thermistor changes resistance with air temperature. The BCM measures this resistance and calculates the temperature of the air drawn into the ATC Control. The ATC system then makes adjustments to maintain the optimum passenger compartment comfort. Refer to the ATC Sensor Motor-Fan Operation table for when the ATC Sensor is operating.

The in-car sensor motor is a separate serviceable part connected to the ATC Control Head. See Diagnosis and Testing for proper check of airflow. The in-Car Sensor Thermistor is part of the ATC Control Head and not a separate serviceable part. One must replace the ATC Control if the ATC self-diagnostics indicates a fault code.

Ambient Air Temperature Sensor

The ambient air temperature sensor is located on the inside of the right front bumper beam. This sensor will inform the ATC system of the ambient temperature outside the vehicle. This sensor is used by the ATC system to adjust blower speed, temperature offsets. evaporator temperatures and mode control.

The ambient sensor is not serviceable and must be replaced if found to be defective.

The ambient temperature sensor is used on all LH vehicles with or without ATC systems.

In-car sensor motor fan test
1. Perform air flow test to check motor/fan assembly.
a. Turn ignition to the ON position and push the OFF button to stop the ATC system airflow. This will make it easier to observe paper in the step Step
b. Place a small piece of newspaper in front of the sensor/motor opening on the ATC control. If the paper sticks to the opening, the In-Car sensor/motor is operating properly. The piece of paper should be only large enough to cover the grille opening.
2. Check if the electrical connection and connector are OK.
3. Check for the two foam seals and their condition, it is absolutely necessary for proper sensor operation.
a. Seal on the inside surface directly behind the nameplate.
b. Seal (strip) located directly to the right of the right center duct opening (instrument panels with trim bezels).

Hello Bill
As for the trim, I have attached pics. It appears to be held in with clips. It always makes me nervous to pull on the plastic parts etc as it is hard to tell at times how it is held in. You might ease a flat tip screwdriver along side and gently pry. Not to small as it may chip. You might put a rag between the screwdriver and the dash to prevent any damage. Some are held in with screws once you remove the ash tray or other surrounding items. But if you look at the pic, it doesn't look like it. Then the next pic shows the back of the panel, removing the plugs. The screws hold the control unit in. You might consider calling the parts department and see if you have to order screws or clips for it. That would be a sure thing. Me, the less you remove the better. I would still just replace the sensor at the front of the car since it is inexpensive. I don't show a check for that though there may be one but if it is intermittent it may check good and then bad on the car. Again, it's the least expensive and so far your check of the ATC shows it is okay. Not sure if this helps. . .. . ...hope so. Good luck.

Bill - if you have time please let me know if that fixes the problem. Also. Me, since that part plays such a big part in the operation of your AC, even if you could get it from a parts distributor, I would get the OEM from the dealer especially since it is not that expensive. Good luck.

Hello Bill,
I see this wants to give us a hard time huh. I only have a few minutes right now but will check back later. If possible can you do this, first, let's make sure we are with the right engine. I show two V6 choices. V6-2.7L VIN R and V6-3.2L VIN J. Which do you have?
Next, have you stopped by Auto Zone or O'Reilly's and had them check for any codes? It's free and that would tell us that is clear. Remember the ATC is supposed to throw a code if not working.

Last, if you haven't driven the car since putting the sensor in, please do so about 3 miles at least. For that matter you will I guess to check the codes.

Let me know and I will check back shortly.

Bob

Bill - seems like you are on the right track and going the same direction I would and it appears others have gone. I will continue to review other items and let you know if I see something else, please keep me posted so I know how you are doing and I may be able to offer more. I agree. Eating the elephant, one bite at a time. Lord willing it is a baby elephant.

Bob

Good morning Bill - glad to see you got the shop manual....it does help.

The erratic/stuck on high fan - here is a troubleshooting chart for that. Still might be that relay....I will check into that and the code 51 for you....gotta run but wanted to get this to you. I'll check more shortly.

Bob

Blend Door Actuator
Body Control Module
Evaporator Temperature Sensor
Mode Door Actuator
Recirculation Door Actuator

Automatic Temperature Control
Body Control Module
Fuse 17 (JB)
G201
Headlamp Switch
Junction Block

Ambient Temperature Sensor
Automatic Temperature Control Power Module
Blower Motor
Body Control Module
Evaporator Temperature Sensor
Fuse 23 (JB)
Junction Block
Mode Door Actuator
Sun Sensor/VTSS Set Led

A/C Compressor Clutch
A/C Compressor Clutch Relay
A/C Pressure Transducer
Fuse 21 (JB)
Fuse B (PDC)
G101
Junction Block
Power Distribution Center
Powertrain Control Module

Fuse 21 (JB)
Fuse B (PDC)
Fuse E (PDC)
G105
Junction Block
Power Distribution Center
Powertrain Control Module
Radiator Fan High Relay
Radiator Fan High/Low Relay
Radiator Fan Motor Assembly

Bill - a couple of other notes.

Service Bulletin
NUMBER: 24-002-04 REV. A

GROUP: Heating & A/C

DATE: July 30, 2004

THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 24-002-04, DATED MARCH 30, 2004, WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDES ADDITIONAL MODEL YEAR.

SUBJECT:
A/C and Heater Performance

OVERVIEW:

This bulletin provides diagnostic information for A/C and heater performance complaints.

MODELS:

1998 - 2004 (LH) LHS/300M/Concorde/Intrepid

2001 - **2005** (JR) Sebring Convertible/Sebring Sedan/Stratus Sedan

NOTE :Perform Customer Satisfaction Notification no. 857, reprogram Powertrain Control Module (PCM), for 2000 model year LH-vehicles built prior to August 30, 1999 (MDH 0830XX).

SYMPTOM/CONDITION:

Erratic operation of the A/C and heater systems including:

Lack of cold air

Lack of hot air

Unrequested mode change - Automatic Temperature Control (ATC) only)

No control of mode or temperature control

Tapping noise from blend door

The above Symptoms may be accompanied by the following Diagnostic Trouble Codes (DTCs):

Blend door feedback

Blend door stall

A/C control mode door input shorted to battery

Mode door stall

In car temp sensor failure ATC messages not received

DIAGNOSIS:

Do not attempt to remove A/C control until after this entire Diagnosis and Repair Procedure has been performed.

Verify customer reported symptom(s) if possible.

Check for the presence of DTCs with the scan tool (DRBIII(R)) and record on the repair order. If a DRBIII(R) is not available reference the appropriate Service Manual - Heating and Air Conditioning "Self Diagnostics" procedure and record any present DTCs on the repair order. If Symptoms and/or DTCs other than those listed above are present, repair as necessary. If a Symptom(s) and/or DTC(s) listed above is present, perform the Repair Procedure.

REPAIR PROCEDURE:

1. With the vehicle at room temperature 10 °- 27 °C. (50 °to 80 °F.), Remove the M-1 circuit fuse for ten minutes to erase DTCs.

2. Install the M-1 fuse and start the vehicle, this will initiate the HVAC system calibration. Allow approximately five minutes for the calibration to complete.

3. Operate the vehicle and HVAC system to verify that Symptoms and/or DTCs are gone. If tapping noise or Blend Stall/Feedback DTCs re-occur, additional diagnosis will be required.

POLICY:
Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:

FAILURE CODE:

Disclaimer :This bulletin is supplied as technical information only and is not an authorization for repair.

I started going over the info, I just don't see this Blower Motor Relay. Can you send me what you have.

SYSTEM OPERATION
The blower motor power module is only used in vehicles equipped with Automatic Temperature Control (ATC). It is located on the lower right side of the HVAC unit housing.

The power module receives pulse width modulated signals from the Body Control Module. The power module varies voltage to the blower motor for different blower speeds based on the ATC software. There are 14 speeds and a blower off signal.

I see the code 51 in the charts but it doesn't give any info about fix. Still checking but wanted to get this to you.

Bob

Bill -
Okay, some more checks based off the codes.

Code 26
NAME OF CODE
In-Car Temperature Sensor Failure

WHEN MONITORED
With ignition on

SET CONDITION
BCM senses an abnormally high or low voltage in the in-car temperature input

THEORY OF OPERATION
The in-car temperature sensor is a thermistor for which the BCM provides a 5V pull-up. Under normal operating conditions (-40 to 85 °C) this voltage should be between 0.313V and 4.88V

PROBABLE CAUSES
"� Wiring open circuit
"� Wiring short to ground
"� Wiring short to battery
"� Failed sensor
"� Failed BCM

Hi Bill...
You can go with number 2. It does seem to be leaning to the thermistor..... Before there were not codes, now there are which if I remember correctly that is what the troubleshooting chart pointed to replacing if there were codes.
The folks at 2CarPros appreciate the donation. Good folks there. Below may name is a area to "Give Feedback" Feel free to put something there if you would like. Also, I haven't been with the 2CarPros folks too long, also feel free to drop Mike Cerjak a note about the service if you would like: mike@2carpros. Com Glad to help... When you are ready to tear back into it... We'll start eating the elephant again. Have a good week at work.

Bob