The Climate control in my 2001 EB Explorer is acting up. Seems like the fan is stuck in the on high position even with the unit 'off', but with other symptoms.

-Fan is on at start-up and remains on.
-Turning climate control off puts it in defrost mode with fan on, display is not illuminated.
-Manually adjusting fan speed control wheel seems to have no effect on fan speed
-When Climate control is off adjusting manual fan control wheel turns display on and out of defrost mode.
-Temp control seems to still work
-Still can cool
-Still can heat
-Auto mode still seems to work as far as temp, but the fan speed stays on high.

Anybody have any ideas about what might be going on and what the solution might be?

I was thinking the unit might have somehow gotten into a strange mode so tried restarting the vehicle several times and also tried disconnecting the battery in hopes it might reset the unit, but no change.
Any ideas are appreciated.

 

First check all the fuses. Then run the control head self test.

The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated. To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank). To exit self-test and clear all diagnostic trouble codes, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared. Always exit the self-test before powering the system down (system turned OFF).
ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX
DTC EATC (Hard) Self-Test Faults EATC (Intermittent) Run-Time Faults Description Action to Take
B1249 024 022 Blend door short
025 Blend door failure Go To Pinpoint Test A <S1NC0003.htm>.
B1251 031 N/A A/C in-vehicle temperature sensor open circuit Go To Pinpoint Test B <S1NC0003.htm>.
B1253 030 N/A A/C in-vehicle temperature sensor short to ground Go To Pinpoint Test B <S1NC0003.htm>.
B1255 041 043 A/C ambient temperature sensor open circuit Go To Pinpoint Test C <S1NC0003.htm>.
B1257 040 042 A/C ambient temperature sensor short to ground Go To Pinpoint Test C <S1NC0003.htm>.
B1261 050 052 A/C solar radiation sensor circuit short to ground Go To Pinpoint Test D <S1NC0003.htm>.
U1073 N/A N/A SCP invalid or missing data for engine coolant REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
U1341 N/A N/A SCP invalid data for vehicle speed REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.

 

HomerWinzlow -thanks for the quick and detailed reply. Followed your instructions -results below preceded by ***.

First check all the fuses.

***Visually inspected both engine compartment and panel by drivers door. All looked OK

Then run the control head self test.

The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated. To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.

***No DTCs were displayed during the test. After the test, the display showed 888 with all other functions symbols illuminated. Waited a few more minutes but the display stayed in that state after the test

To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank).

***Pushing the blue button finally cleared the display "off" but the fan was still blowing.

To exit self-test and clear all diagnostic trouble codes, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared.

***Pushing the defrost button put the unit in defrost mode and turned on the display.
Any other things that can be checked?

 

My guess is a bad blower speed controller. It is the EATC equivalent of the manual AC blower resistor. They have updated them and the new version comes with a new type pigtail wiring and you cut off the old pigtail connector and install the new type. If all power sources are good and the control detects no problems with sensors then that would be my first place to look.

 

Before springing $50 for the blower speed controller I tried unplugging it at the blower in the engine compartment.
My thought was... if the fan stiil ran when the ignition was turned on then it would be pretty conclusive that the blower speed controller was bad.
'Course nothing ever works to make things simple and the fan now did not run when the system was turned on. I proceded to reconnect the cable to the blower speed controller and disconnect the harnesses from the rear of the EATC. Fan did not operate when the ignition was turned on. So ... on the surface the EATC seems to be causing the problem? But knowing what happens when one assumes...

Could it still (hopefully) be the blower speed controller given the test above? Is the only way to prove/disprove it to install a new blower speed controller? Acording to dealer the EATC is ~$500 part! Any thoughts?

 

Hi

I found this thread while searching for an answer to the very same problem on my explorer. Have you had any luck since then with the climate controll. I haven't tried the step mentioned yet, but I wanted to see if you had came to a conlusion. Thanks for any help you can give me.

Derrick

 

It got to a mode where I can now manualy turn the fan both on and off. High speed only though. That has been OK to get me through the winter. If this New England winter ever ends (seems questionable!) I plan to pick up a blower speed controller for a few bucks from a salvage yard as a test.

 

Thats just crazy since I posted last, my explorer has done the exact same thing. One day I climbed in and started it up and the blower didn't blow me away as usual. I hit the fan control, and on it came. So magically just like you described I have control of on or off but its ALL or nothing. Which is better than it was,.. at least now I can turn it off. I though it was really strange but now knowing that yours did the exact same thing,... wow. I too am going to tuff this out with the current fan situation,... atleast for quite a while, (short on cash). Please let me know how it goes when you end up getting a blower speed controller. I'd love to hear if you have any success. Thanks again for the info. It makes me feel better knowing someone else is going through the same frustrations. Good luck.!

Demerson1