Max A/C problem
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From: South Texas
Max A/C problem
I have an 02 screw with the elec hvac system.
This started in like october?
If I choose max a/c or set it to 60 deg auto it blows out the defrost vents only.
If it's in auto at anything above 60 it works perfectly like it should.
I had someone tell me its because my system cant cool the air down enough to put it through the main vents. I personally don't think thats the problem but any suggestions will be appreciated.
This started in like october?
If I choose max a/c or set it to 60 deg auto it blows out the defrost vents only.
If it's in auto at anything above 60 it works perfectly like it should.
I had someone tell me its because my system cant cool the air down enough to put it through the main vents. I personally don't think thats the problem but any suggestions will be appreciated.
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From: South Texas
Originally Posted by projectSHO89
EATC is hosed.
Steve
Steve
???
are you talking about the hoses connected to the rear of the eatc?
sorry im good with vehicles with hvac is a whole nother world
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From: South Texas
[QUOTE=torkum]Steve is saying the $400.00 control unit is bad 
[QUOTE]
thats what i was afraid of. would it be a good idea to take it somewhere & have it looked at before i rip my wallet open for a new EATC?
[QUOTE] thats what i was afraid of. would it be a good idea to take it somewhere & have it looked at before i rip my wallet open for a new EATC?
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Joined: Oct 2002
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From: St. Louis (Out in the woods)
You can run the EATC self test to see if it indicates any faults as follows (from the factory service manual):
The reason I suspect the head unit itself is because the symptom is only apparent in a very specific set of circumstances. Because all the logic of airflow selection is under the control of the computer in the EATC and you're seeing illogical symtoms..well, Spock could say it well.
Faced with that cost, I'd learn to live with a 65 degree setting for awhile!
Steve
Electronic Automatic Temperature Control Module Self-Test
The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A scan tool must be used to retrieve these concerns.
The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40°-90°F) when performing the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
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.
If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
To exit self-test and retain all intermittent DTCs, push the blue (cooler temperature) button. The control will exit self-test, retain all intermittent DTCs and then turn OFF (display blank).
To exit self-test and clear all DTCs, 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).
Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.
The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A scan tool must be used to retrieve these concerns.
The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40°-90°F) when performing the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
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.
If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
To exit self-test and retain all intermittent DTCs, push the blue (cooler temperature) button. The control will exit self-test, retain all intermittent DTCs and then turn OFF (display blank).
To exit self-test and clear all DTCs, 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).
Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.
Faced with that cost, I'd learn to live with a 65 degree setting for awhile!
Steve
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Thread Starter
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Senior Member
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From: South Texas
Originally Posted by projectSHO89
The reason I suspect the head unit itself is because the symptom is only apparent in a very specific set of circumstances. Because all the logic of airflow selection is under the control of the computer in the EATC and you're seeing illogical symtoms..well, Spock could say it well.
Faced with that cost, I'd learn to live with a 65 degree setting for awhile!
Steve
Faced with that cost, I'd learn to live with a 65 degree setting for awhile!
Steve
I dunno if this will help any but the first time this happened was last Oct i was going down the road & was reachin for the temp up button when i hit a hole in the road & accidently made me hit max a/c & its been like this since.
Oh & when i have the unit turned off hot air comes out of the vents & if i close the vents it comes out the floor.
Dunno if any of that helps but its just some more symptoms.
Thanks Again Steve.
Hmmmm....I wonder if I can go pull the EATC out of my totaled truck
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From: South Texas
Well, I tried the EATC self-check. It did the lil scrolling line thing & when it stopped the screen showed everything on it. I took a pic but can't post it yet, I'll try a lil later today.
Whats this symptom chart condition?
Whats this symptom chart condition?
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Joined: Oct 2002
Posts: 7,295
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From: St. Louis (Out in the woods)
Originally Posted by sean_somer
Whats this symptom chart condition?
Here ya go, the full diagnostic procedure you can download and follow: http://www.mediafire.com/?avwbmyd9yhe
Steve
2009 F150online Truck of the Year
Joined: Jul 2006
Posts: 1,190
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From: GATOR NATION, FLA
I had the same exact problem with mine, it was the control unit. My local Ford Stealership wanted $700 for one I had an extended warranty that paid for it....Thank goodness 
I had an extended warranty that paid for it....Thank goodness
Thread Starter
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Senior Member
Joined: Apr 2006
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From: South Texas
Originally Posted by projectSHO89
It's a diagnostic chart based on observed (mis)operation of the unit in the service manual.
Here ya go, the full diagnostic procedure you can download and follow: http://www.mediafire.com/?avwbmyd9yhe
Steve
Here ya go, the full diagnostic procedure you can download and follow: http://www.mediafire.com/?avwbmyd9yhe
Steve
I found the chart & went through it but didnt have my truck at the time so couldnt do it all but Im going to do it monday so Ill let yall know how it went.
Originally Posted by GATOR CREW
I had the same exact problem with mine, it was the control unit. My local Ford Stealership wanted $700 for one I had an extended warranty that paid for it....Thank goodness
I had an extended warranty that paid for it....Thank goodness Yeah, not looking forward to purchasing one, my only hope is I can get the one out of my totaled truck
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Joined: May 2002
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From: San Antonio, TX
I am having this issue now. Here are my symptoms.
02 F150 Supercrew 4.6 with the digital Automatic Climate Control system.
When set in either Automatic or Max AC @ 60 degrees air will only flow from defroster vents.
If I set the temp @ 74 and up in Auto or Max air will flow normally from just the dash vents. So right now the only way to get air from the dash vents at temps below 74 is to put it in Dash/floor mode.
Also when air is coming from all the dash vents and you are accelerating and you hit 45, 55, 65, or 75 MPH, the air will stop flowing from the dash vents and switch to the defroster vents only. If you let off the gas a bit, then it will switch back to the dash vents only until you hit the next listed speed.
I have checked for vacuum leaks in all the underhood lines, and even checked the vacuum canister for cracks/leaks.
Did you ever determine it was the EATC or the blend door that was the problem?
02 F150 Supercrew 4.6 with the digital Automatic Climate Control system.
When set in either Automatic or Max AC @ 60 degrees air will only flow from defroster vents.
If I set the temp @ 74 and up in Auto or Max air will flow normally from just the dash vents. So right now the only way to get air from the dash vents at temps below 74 is to put it in Dash/floor mode.
Also when air is coming from all the dash vents and you are accelerating and you hit 45, 55, 65, or 75 MPH, the air will stop flowing from the dash vents and switch to the defroster vents only. If you let off the gas a bit, then it will switch back to the dash vents only until you hit the next listed speed.
I have checked for vacuum leaks in all the underhood lines, and even checked the vacuum canister for cracks/leaks.
Did you ever determine it was the EATC or the blend door that was the problem?