AC not working correctly

I don't show Concorde until '93 so here's the self diagnostic for 93 ok? SELF-DIAGNOSTIC SYSTEM Entering Self-Diagnostics 1. Ensure A/C-heater control panel is set to display degrees Fahrenheit ( °F). Start engine (vehicle not moving) and set temperature control to 75 °F. To enter self-diagnostic mode, press and hold floor, mix (floor/defrost) and FRT (front) defrost buttons at the same time. See Fig. 2 . When ATC panel display begins to blink, release all 3 buttons. 2. The display will continue to blink until it completes its tests and calibrations. Any diagnostic trouble codes stored in BCM that are related to ATC will be displayed when blinking stops. If there are no trouble codes, system will return to normal operation. 3. Trouble codes will appear on display in numerical form. Only one number will be displayed at a time. Press panel (vent) button to scroll through any additional trouble codes. See DIAGNOSTIC TROUBLE CODES table for list of codes. Exiting Self-Diagnostics & Clearing Codes To exit self-diagnostics, turn ignition off. To clear codes, disconnect negative battery cable (power supply to BCM) for at least 10 minutes. NOTE: If ATC in-vehicle temperature sensor is disconnected while self- diagnostic system is running, Code 26 will set and display will go blank.

Typo, my concord is a 1998, not a 1989. Will this same info apply? the controls look different. Again sorry for the error on my part. I am new to your site but I am VERY impressed with what I see. Thanks for your help.
Looking at older post I see i am not the first to have this issue. Also I read some related posts and I have symptoms that I did not know were related....

1. Fan blower runs wide open all the time, even when AC is off. (You knew this)
2. AC compressor will not start up. (you knew this)
3. From time to time interior lights will blink on then off all by themself. (I did not tell you this in the first post, did not know it was related)

Here's the proceedure for 98': IN-VEHICLE CALIBRATION & DTC CHECK 1. ATC system door/actuator calibration compensates for mechanical differences in actuators and A/C-heater assembly. Floor, mix and front defrost buttons and blower motor control selector are used for ATC system door/actuator calibration and to check for any ATC system DTC stored in BCM. 2. Set parking brake and place transmission in Park position. Start engine and ensure vehicle does not move. Set ATC control head temperature to 75 °F so that any displayed DTC will not be confused with a displayed temperature. 3. Turn blower motor control selector counterclockwise, to off position. Simultaneously press and hold floor, mix and front defrost buttons. See Fig. 1 . Release buttons when ATC control head display begins to blink, indicating ATC control head has entered calibration/diagnostic mode. ATC control head display will continue to blink until door/actuator calibrations and ATC system DTC check are completed. 4. If ATC system is okay and there are no stored DTCs, system will return to normal operation and temperature symbol "F" or "C" will be displayed. If there is a stored DTC, a two-digit DTC will be displayed. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTICS for BCM DTC identification. To exit calibration/diagnostic mode, turn ignition off. SELF-DIAGNOSTICS * PLEASE READ FIRST * RETRIEVING DIAGNOSTIC TROUBLE CODES 1. Diagnostic Trouble Codes (DTCs) related to the ATC system are stored in the Body Control Module (BCM). Any BCM DTC present, will be displayed on ATC control head display when in-vehicle calibration and DTC check is completed. See IN-VEHICLE CALIBRATION & DTC CHECK under ADJUSTMENTS. ATC control head will display a two-digit DTC. See IDENTIFYING DIAGNOSTIC TROUBLE CODES table. If system is okay and there are no system DTCs present, system will return to normal operation. 2. There are certain conditions in which more than one ATC system DTC can be stored in BCM. ATC control head display can show only one DTC at a time. Press panel mode button to scroll through any additional DTCs. If any other button or selector is moved or pushed, additional NOTE: Changing any ATC control head selector or button position unless instructed to do so, will abort door/actuator calibration and Diagnostic Trouble Code (DTC) check. System will return to normal operation. During in-vehicle calibration and DTC check engine must be running and vehicle not moving. NOTE: There may be DTCs stored in Powertrain Control Module (PCM) that are not related to ATC system DTCs which are stored in Body Control Module (BCM). There are some PCM DTCs that identify problems affecting ATC system operation. DTCs will not be displayed. To exit in-vehicle calibration DTC check, turn ignition off. CLEARING DIAGNOSTIC TROUBLE CODES DTCs can be cleared from BCM memory using a scan tool or by disconnecting negative battery cable remote terminal for 10 minutes. Negative battery cable remote terminal is located on right strut tower. If using a scan tool to clear DTCs, refer to scan tool manufacturer instructions. NOTE: If in-vehicle temperature sensor is disconnected while Body Control Module (BCM) is operating, DTC 26 will set. This can occur when BCM or ATC control head connectors are disconnected when battery is connected (even with ignition off). To correct condition, clear Code 26 from BCM. See CLEARING DIAGNOSTIC TROUBLE CODES . 10/5/2009 ...

Ran self diagnostic process, got code 26 but I had disconnected the ATC last week. Followed code clearing procedure and repeated self diagnostic, no codes this time. Even ran self diagnostic after driving to work today, still no codes. Then went to Auto Zone and had them test the BCM for codes but he said his test would not pick up any codes for any accessories only engine codes. I have a coworker who has a code test unit, I hope to get it and have him check for any ATC codes on the BCM. I will advise what I find.

If you cleared the codes, and they dont set again, it will not find any...does it work right now?

No codes in ATC but fan still blowing at max speed & compressor still not starting up. I understood from the 98 ATC procedure you gave me that I also need to check for DTC's in the BCM & the PCM. Yes???

NOTE: There may be DTCs stored in Powertrain Control Module (PCM) that are not related to ATC system DTCs which are stored in Body Control Module (BCM). There are some PCM DTCs that identify problems affecting ATC system operation.

I saw on another post that the ambient temp sensor could be bad and could cause the fan to run all the time, I have replaced this but no change in fan operation. (cost $15.00)

I now have a used ATC control unit on order, ($50.00) due in Friday. Am I wasting my money?

Code 26 is for the inside temp sensor, is that the one you replaced? TEST 17A: INCORRECT BLOWER MOTOR SPEEDS 1. Turn ignition on and operate blower motor. If blower motor is stuck on high speed, go to next step. If blower motor is not stuck on high speed, replace ATC control head. Perform VERIFICATION TEST . 2. Locate Body Control Module (BCM), attached to junction block, at left end of instrument panel. See Fig. 4 . Turn ignition off. Remove BCM from junction block. Ensure 20-pin internal connector terminals are clean and tight. See Fig. 6 . Repair as necessary. 3. Using an ohmmeter, measure resistance between ground and junction block 20-pin internal connector terminal No. 20. If resistance is less than 5.0 ohms, go to next step. If resistance is more than 5.0 ohms, repair open in junction block ground circuit. Perform VERIFICATION TEST . 4. Using an ohmmeter, measure resistance between ground and junction block 20-pin internal connector terminal No. 1. If resistance is less than 5.0 ohms, go to next step. If resistance is more than 5.0 ohms, repair open in junction block ground circuit. Perform VERIFICATION TEST . 5. Disconnect blower motor power module 4-pin connector. Ensure connector terminals are clean and tight. Repair as necessary. Turn ignition on and engine off. Using a voltmeter, measure voltage between ground and power module 4-pin connector terminal No. 4 (Dark Green wire). If voltage is less than one volt, go to next step. If voltage is more than one volt, repair short to battery voltage in Dark Green wire. Perform VERIFICATION TEST . 6. Turn ignition off. Reconnect blower motor power module 4-pin connector. Connect a jumper wire between ground and BCM Black 24-pin connector C2 terminal No. 6 (Red/Light Green wire). Turn ignition on. If blower motor still operates at high speed, go to next step. If blower does not operate at high speed, replace BCM. Perform VERIFICATION TEST . 7. Turn ignition off and remove jumper wire. Disconnect blower motor power module 4-pin connector. Using an ohmmeter, measure resistance of Red/Light Green wire between BCM connector C2 terminal No. 6 and power module 4-pin connector terminal No. 3. If resistance is less than 5.0 ohms, go to next step. If resistance is more than 5.0 ohms, repair open in Red/Light Green wire. Perform VERIFICATION TEST . 8. Using an ohmmeter, measure resistance between ground and power module 4-pin connector terminal No. 2 (Black wire). If resistance is more than 5.0 ohms, repair open in Black wire. If resistance is less than 5.0 ohms, replace blower motor power module. Perform VERIFICATION TEST . NOTE: Perform TEST 1A: IDENTIFYING ATC SYSTEM PROBLEMS before proceeding with this test.

VERIFICATION TEST 1. Reconnect all previously disconnected components and wiring. If Body Control Module (BCM) has not been replaced, go to next step. If BCM has been replaced, use DRB (scan tool) to program all Remote Keyless Entry (RKE) transmitters, recalibrate ATC system doors and program other options as necessary. 2. If ATC system has been repaired or battery has been disconnected, ATC door actuators must be calibrated. Start engine and use scan tool to calibrate door actuators. DO NOT allow vehicle to move during door actuator calibration. Turn engine off and go to next step. 3. Turn ignition on. Using scan tool, erase Diagnostic Trouble Codes (DTCs). Turn ignition off and wait at least 5 seconds. Turn ignition on (engine off) and fully operate repaired system to verify correct operation. If system operates properly, go to next step. If system does not operate properly, go to TEST 1A: IDENTIFYING ATC SYSTEM PROBLEMS . 4. If A/C-heater system operates properly, use scan tool to check for other BCM DTCs. If any BCM DTCs are present, go to TEST 1B: IDENTIFYING ATC SYSTEM BCM DIAGNOSTIC TROUBLE CODES test. If no BCM DTCs are present and original DTC cannot be duplicated, repair is complete.

No I have not replaced the inside temp sensor I replaced the outside temp sensor. I read on another site that the ATC uses the difference between the outside and inside temps to drive the blower speed. Anyway it had no effect.
After reading this last test info you provided my head hurts. I will read over this, call my friend with a PhD and let you know what I find, or don't find. Good information just the same. This must be the test the dealer told me about that takes tons of time and talent. I fear I am lacking on the latter!

What it boils down to is if the temp reading for outside air temp seems right, then the sensor is OK, your problem is most likley you need to replace blower motor power module.

Will the blower motor power module have any effect on the compressor? or just the fan? Also where is the blower motor power module? Is this what is call a blower motor resistor that is located near the blower motor? Thanks for all your help.

You have automatic temperature control then it's as stated, if you have a manual a/c system, then it's the resistor. BLOWER MOTOR POWER MODULE Removal & Installation Disconnect negative battery cable remote terminal, located on right strut tower. Remove lower right underpanel silencer duct. Disconnect blower motor power module connector. Remove blower motor power module. To install, reverse removal procedure. IN-VEHICLE TEMPERATURE SENSOR Removal & Installation Locate in-vehicle temperature sensor aspirator fan assembly at back of ATC control head. Remove ATC control head and remove aspirator fan assembly screws and remove fan assembly. To install, reverse removal procedure. NOTE: In-vehicle temperature sensor is composed of a temperature thermistor and a sensor aspirator fan assembly. Temperature thermistor is serviced as part of ATC control head. If temperature thermistor replacement is required, ATC control head must be replaced.

A/C must be charged enough so the low pressure cutout switch will let it run, also there is a relay for the clutch in the power distribution center(fuse box) under the hood.

ATC on order, due in today.
BMPM on order, due in next week.
Checked compressor, has plenty of coolent.

Will get back to you when parts come in.

Again many thanks.

Donated again, can I get an answer to the below question?

Merlin, great news. I received and installed the BLOWER MOTOR POWER MODULE as you instructed and now the blower fan operates properly. YES! I purchased it used on e-bay for $65 dollars, new from a parts store was $135!
Now the bad news, the compressor still will not come on. I jumped it out again and it will run and has plenty of coolent. Also not sure if I told you this but when I first removed the ATC unit a penny droped out of the small slots in the dash where the air is pulled in across the inside temp sensor. Could the penny have shorted out the sensor and now the ATC thinks it is -29 degrees in the car and will not allow the compressor to start up? I re-ran the ATC dianogostic and GOT NO ERROR CODES. Also when in auto mode if I lower the temp setting the fan slows down so I question if the ATC is perhaps working correctly???
I had a ATC unit ordered but when it came in the supplier had shipped the wrong part! I have found one on e-bay from the same person who sold me the blower motor power module. Price... $65 vs $135 from the parts house. (both are used but tested)
Your help has been great, what do I do next to get the compressor working?

Have you checked the charge with manifold gauge set? Most common problem is low charge! Even with compressor not running, it will need a reading of 70-100 psi for compressor to kick in.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Please let us know what happens.

Cheers