1998 Chrysler Concorde Auto Temp Control

Tiny
LGB BILL
  • 1998 CHRYSLER CONCORDE

Air Conditioning problem
1998 Chrysler Concorde 6 cyl Front Wheel Drive Automatic 128000 miles

For the last several years, my automatic temperature control has slowly been losing the ability to maintain temperature.

It started with erratic fan speed. With everything working correctly, temp at 73 degrees, all of a sudden the fan would go to full speed and the temp would go full hot or full cold. Sometimes it would only be a temporary problem and then work fine for another few weeks.

Eventually, it became so much of a hassle that I just started using the manual mode for operation.

A few days ago, the fan went immediately to full speed and hasn't responded to any manual attempts to adjust the speed. Even with the system selected to "Off", the fan runs at full speed.

I've had the car to the dealer twice, a general automotive repair shop once, and to two A/C shops. Each time, they say that they can't find anything wrong with the system, meaning that the system is not setting any fault codes.

I've tried the process of resetting the A/C system using the buttons on the temp controller with no luck.

I know that the components of the A/C system are actually controlled by the Body Control Module, with input from the temp controller. I really don't want to just start "shotgunning" the process by replacing parts until I stumble into what is wrong.

Suggestions?

Thanks,
Bill

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Wednesday, October 8th, 2008 AT 3:54 PM

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Tiny
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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).


http://www.2carpros.com/forum/automotive_pictures/248015_Ambient_Sensor_1_1.gif



http://www.2carpros.com/forum/automotive_pictures/248015_Ambient_Sensor_2_1.gif



http://www.2carpros.com/forum/automotive_pictures/248015_ATC_Sensor_MotorFan_1_1.jpg



http://www.2carpros.com/forum/automotive_pictures/248015_ATC_Sensor_MotorFan_2_1.gif

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Wednesday, October 8th, 2008 AT 6:26 PM
Tiny
LGB BILL
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OUTSTANDING REPLY!

Very good analysis and suggestions. I'll be working on these over the next several days. Where the front end sustained major damage several years ago, I'm suspecting the ambient air temp sensor.

I'll let you know what I find.

Thanks for the great service!

Bill

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Thursday, October 9th, 2008 AT 12:04 AM
Tiny
LGB BILL
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So far, I've verified that the in car sensor motor and fan are drawing air in through the intake.

I'll take a look at the ambient temperature sensor as soon as I can crawl under the car and locate it. Is there any testing that can be done on the ambient sensor, such as resistance tests with varying temps?

Is it possible to verify that the trim around the ATC head is only held in place with a few screws in the lower area? Once those are out, I'm guessing the trim should be easily removed and the ATC head can be worked on.

Thanks again for your help!

Bill

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Thursday, October 9th, 2008 AT 12:13 PM
Tiny
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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.


http://www.2carpros.com/forum/automotive_pictures/248015_ATC_Head_removal_1_1.gif



http://www.2carpros.com/forum/automotive_pictures/248015_ATC_Head_removal_2_1.gif

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Thursday, October 9th, 2008 AT 7:35 PM
Tiny
LGB BILL
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I've located and removed the ambient temp sensor. Interestingly, that had no effect on the operation of the blower speed. That could indicate the sensor is open, resistance-wise. I haven't had the time to test it to see what resistance might be there.

I've also managed to remove the trim and look at the ATC head. All appears to be okay in that department. You were right; it IS scary pulling on the plastic. Once I got it out, I can see that it's not that big a deal for future work in that area.

Tomorrow I'ill buy the ambient temp sensor and replace it. With luck that will be the culprit.

Again, thanks for your excellent advise and guidance.

Bill

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Thursday, October 9th, 2008 AT 11:06 PM
Tiny
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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.

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Thursday, October 9th, 2008 AT 11:34 PM
Tiny
LGB BILL
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Good afternoon.

Well, I purchased an OEM ambient temp sensor and replaced it. No change in the symptoms.

As part of trying to get it working, I started trying to use the "Auto" mode. I was able to get it into the auto mode for a while and could feel that it was regulating the temp to about what was set on the ATC head. But, it was still in the high speed mode for the blower, which I believe was causing it to "hunt" the temperature a little bit.

Subsequently, the ATC head dropped out of the auto mode all by itself. I now recall that the ATC head really doesn't want to work in auto at all. Most times, it ignores any attempt to select auto. Most components seem to be doing what they should, such as the temperature blending valve and the various distribution valves. The parts that are not cooperating are the blower (speed) and the auto temp operation. One indicator might be the failure of the selected temperature to be displayed most of the time.

I used to know how to run the self diagnosis on the ATC head, but have lost the procedure. Do you know how to do that test?

I'm now quessing that the ATC head might be next in line for replacement. I've been told I can find one at a "Pick Your Part" lot for about $50.00.

Thoughts?

Thanks for sticking this out with me!

Bill

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Friday, October 10th, 2008 AT 2:44 PM
Tiny
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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

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Friday, October 10th, 2008 AT 5:08 PM
Tiny
LGB BILL
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Thanks for the quick response, Bob.

It's a 3.2L.

More info. I actually removed the temp sensor last night in preparation for getting the replacement this morning. SURPRISE! It really didn't like that. When I drove the car this am, I had a Check Engine light and the battery annunciator illuminated? In any case, as soon as I got to my first desination, I replaced the sensor and the battery annunciator went out. The check engine light stayed on until after leaving the second destination where I installed the new sensor.

I have a OBD II tester at home and will check for codes there.

Gotta run home. Wife just told me her battery is dead.

SHEESH!

Thanks,
Bill

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Friday, October 10th, 2008 AT 5:19 PM
Tiny
LGB BILL
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The saga continues.

The OBD II indicated a code for low voltage from the ambient/battery temp sensor. With the temp sensor removed yesterday, it set the code, but gave the battery annunciator. Cleared the code.

Researching other forums, it is looking more like multiple problems here. The blower running at max all the time is indicative of the blower moter solid state relay being failed (goes to high mode typically).

The ATC head is not going into the self test mode with the three right hand buttons pushed in. Also, the modes of the ATC head change erratically. I.E, the temperature display occasionally goes blank. The mode will either change from auto to manual or not go into auto at all. Some have had success by tapping the ATC head, which could indicate a poor electrical connection or solder joint somewhere in the unit.

Next step will be to replace the blower relay since it seems to be the most likely culprit for the immediate problem of the blower running at max all the time. If I can regain control of the blower speed, I can work on tracking down the issue with the ATC auto mode not working. Rebuilt ATC heads are available for $80 plus $10 shipping. Blower relays are $65 plus shipping.

Eating the elephant, one bite at a time.

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Sunday, October 12th, 2008 AT 1:54 AM
Tiny
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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

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Sunday, October 12th, 2008 AT 2:05 AM
Tiny
LGB BILL
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Hi Bob.

Just figured out the correct way to run the DTC for the ATC head. Was pushing wrong buttons earlier and not getting any results.

The DTC indicates a code of 51 - System Voltage Too Low For Door Calibration. Drat! I wanted to see a code that said "ATC Head All Messed Up" or "Blown Fuse" or something simple. Never my luck.

I'm not sure what to do with this code 51. This almost sounds like a wiring problem. I'm thinking I'll still head over to Pick Your Part tomorrow and get myself a replacement blower relay for starters.

FYI. I went ahead and subscribed to the repair manual. I figure this will help with figuring out how to disassemble the beast if it comes down to it.

Too be continued.

Bill

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Sunday, October 12th, 2008 AT 2:26 AM
Tiny
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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


http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_1_1.jpg




http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_2_1.jpg




http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_3_1.jpg




http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_4_1.jpg




http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_5_1.jpg




http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_6_1.jpg



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


http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_7_1.jpg



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


http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_8_1.jpg



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


http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_9_1.jpg



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


http://www.2carpros.com/forum/automotive_pictures/248015_Fan_Speed_10_1.jpg



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

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Sunday, October 12th, 2008 AT 11:02 AM
Tiny
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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

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Sunday, October 12th, 2008 AT 11:25 AM
Tiny
LGB BILL
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Hi Bob.

I'm sorry for the red herring about the "blower motor relay". It is properly called the blower motor power module. The "relay" came from some other on-line resources that referred to it as a "solid state relay" which is probably a technically correct description but not what is commonly used in the manuals.

I have found more codes. I didn't figure out how to page from the first code to the rest until I sat in the car again and tried to figure out what they meant by "panel switch". "Panel" here refers to the A/C outlets in-dash.

The full complement of codes is now: 51 [System voltage too low for door calibration], 26 [ATC thermistor failure], and 35 [Evaporator sensor failure].

I don't know what the 51 is all about; I think it'll be on the back burner. Regarding the ATC thermistor, I'm leaning toward replacement of the ATC head on that one. And, regarding 35, again, it'll be back burner.

With the info you've provided I've got some more testing to do. I think it would be wise to erase the DTC codes via removal of the M-1 fuse and start with a clean slate to see what's real and what's not.

Will probably do some more later this evening and will post what I've found.

Thanks for all you're doing, Bob. Way beyond what anyone might expect!

Take care,
Bill

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Sunday, October 12th, 2008 AT 7:09 PM
Tiny
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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


http://www.2carpros.com/forum/automotive_pictures/248015_Code_26_a_1.jpg



http://www.2carpros.com/forum/automotive_pictures/248015_Code_26_1.jpg

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Monday, October 13th, 2008 AT 2:26 AM
Tiny
LGB BILL
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Hi Bob.

Thanks again for your response. I'm guessing from the time-stamp on your response that: (1) You are recieving a really good salary to do this work and thereby motivated by the pay, or (2) you really do enjoy this kind of challenge and get a lot of satisfaction from seeing a job finished. Hmmm. I'll put my money on # 2!

Where I'm back into the "work week" mode, I'll have a little less spare time to peck away at this beast. With the latest input and the previous post, I have some really good specific issues to check and can make the most of my time. My money would be on a defective in-car temp sensor just based on intuition and what is available from the symptoms.

As soon as I can run these latest tests, I'll let you know. I'm really hoping to find the ATC thermistor is defective because I really don't want to tackle tearing apart the dash to gain access to the BCM.

As soon as I have more to post, I'll do it.

FYI. I've made another small contribution to the web site. I feel a liitle guilty getting all of this help for the small donation I made earlier. Even with donations, I know that this is more than for just the money. Knowing that, I appreciate your help very much!

Later,
Bill

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Monday, October 13th, 2008 AT 10:32 AM
Tiny
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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

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Monday, October 13th, 2008 AT 6:48 PM
Tiny
LGB BILL
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Hi Bob.

To make sure I wasn't chasing a phantom, I cleared the codes. After running the "In-vehicle Calibration and DTC Check", there are now no codes.

I keep coming back to the primary symptom of the blower speed being stuck at high. This takes me to the "TEST 17A: INCORRECT BLOWER MOTOR SPEEDS". Reading through this area, it appears the most likely culprit is the blower motor power module. The only way to be 100% certain though is to go through the entire set of tests that are listed in 17A. I'm really tempted to just buy a used power module and replace it rather than tear apart the dash to get the BCM out for testing. I know that's not the professional approach to this issue, but time-wise, it seems like it might be the easier route. Not having taken the BCM out yet, I'm just guessing that it is a chore. I might be wrong.

Another problem I have is that I bought an inexpensive DRB II code reader and everything I read in the manual indicates that the only way to really get the detailed info is to use a "scan tool" to test the many individual parts of the system.

It still seems like multiple problems, most likely being the blower motor power module, with the background issue being the ATC head.

Out of time tonight.

Good night, Sir.

Bill

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Tuesday, October 14th, 2008 AT 1:37 AM
Tiny
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Sorry. That was supposed to be OBD II code reader.

Brain dead last night.

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Tuesday, October 14th, 2008 AT 10:00 AM

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