AC Warm at "Max AC"

[MountaineerMonte]

My wife has a 2000 Mountaineer 5.0 V8. We had a problem with low idle and I cleaned out the EGR valve which fixed the problem. Now the AC will not get cold. I brought it to a local mechanic for a recharge, which they did, they charged 250 to remove the passenger air bag to inspect the blend door actuator. They describe the issue as the actuator/blend door.

From reading previous posts, my understanding was that if the AC will not blow cold on "Max AC", the problem is not likely to be the actuator or the blend door. They state that the compressor is good/engaging.

Any suggestions before I go down the road of the actuator & blend door repairs?

 

[ian1739]

Not sure if a 2000 is the same as a 98, but if you have EATC try this out first. If you get a 024 or 025 code then it's a relative easy fix of a broken actuator. More than likely though, you will not get any DTCs and it will be a broken blend door, which is quite a pain to repair.

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 NGS tester 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 (DTC) 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) 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).
Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.


Powertrain Control Module Diagnostic Trouble Code (DTC) Index DTC Description Action
P1460 WOT A/C cutout circuit malfunction REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
P1464 A/C demand out of self test range GO to DTC P1464.

ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX NGS DTC EATC Description Action to Take
(Hard) Self-Test Faults (Intermittent) Run-Time Faults
B1249 024 022 Blend door short
025 Blend door failure GO to DTC B1249.
B1251 031 N/A A/C in-car temperature sensor open circuit GO to DTC B1251.
B1253 030 N/A A/C in-car temperature sensor short to ground GO to DTC B1253.
B1255 041 043 A/C ambient temperature sensor open circuit GO to DTC B1255.
B1257 040 042 A/C ambient temperature sensor short to ground GO to DTC B1257.
B1261 050 052 A/C solar radiation sensor circuit short to ground GO to DTC B1261.
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.

Good luck!

 

[TheJackal]

From reading previous posts, my understanding was that if the AC will not blow cold on "Max AC", the problem is not likely to be the actuator or the blend door. They state that the compressor is good/engaging.

Yeah, if you have it in "Max A/C," the heater core is bypassed so there isn't any heat in the plenum, and the position of the blend door is irrelevant.

I suppose it could be possible for both the blend door actuator and the coolant bypass valve to both malfunction at the same time, but it seems unlikely.

Did they check the actual pressure of the A/C system at the shop? Do you have any known vacuum leaks?

 

[ian1739]

Unlikely to have both problems, but possible. When I tackled my blend door problem, I found that the heater core was hot all the time, even in max a/c. I popped the hood and followed the coolant lines until I found the water diverter valve, (located underneath the alternator in my 98) and sure enough the vacuum line had rubbed up against the exhaust manifold and melted. Luckily enough when it melted, it sealed itself at both ends and kept out the moisture and I didn't have any vacuum leaks.

Using an electrical #10awg butt-splice, some liner-less rubber splicing tape, and some super88 (high temp/quality) electrical tape I was able to fix the hose that I'm sure is worth a small fortune from ford. Here's what it looked like fixed:

It only took 10 minutes to fix, and now when I hit MAX A/C I can watch the valve do its thing. Like you say, its not likely that both would be broken, but possible.

 

[Nexor]

I'm having this same problem. I found the vacuum lines going to the vacuum reservoir globe melted. They were melted open, hopefully not to much dust got in. When this happened hot air was blowing out of the defrost ports all the time. I fixed the melted lines going to and from the reservoir and now my vents work but only blow hot air out, even on max A/C setting. I tried bypassing the vacuum globe and still same problem. Feels like my heater core is hot in under the passenger side but unable to 100% verify. Before my lines melted all was working fine.

Are you saying there is another vacuum line that goes to the "water diverter valve?". Does this line originate at the top of the motor next to the EGR sender and run down to under the alternator?

 

[Nexor]

Found the cause, the gray vacuum line for the heater core bypass was melted and need to be repaired and plugged back in. A/C is pumping out cold air now. Heater water value was located under the alternator as previously stated.

 

[TYOUN123]

My 2000 mountaineer suddenly stopped blowing hot and cold air. The compressor is good and the vacuum lines are as well. I belive it is the solar radiation sensor but I cannot find anyone to sell me the part. any suggestions?

 

[harley75]

Not sure if a 2000 is the same as a 98, but if you have EATC try this out first. If you get a 024 or 025 code then it's a relative easy fix of a broken actuator. More than likely though, you will not get any DTCs and it will be a broken blend door, which is quite a pain to repair.

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 NGS tester 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 (DTC) 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) 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).
Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.


Powertrain Control Module Diagnostic Trouble Code (DTC) Index DTC Description Action
P1460 WOT A/C cutout circuit malfunction REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
P1464 A/C demand out of self test range GO to DTC P1464.

ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX NGS DTC EATC Description Action to Take
(Hard) Self-Test Faults (Intermittent) Run-Time Faults
B1249 024 022 Blend door short
025 Blend door failure GO to DTC B1249.
B1251 031 N/A A/C in-car temperature sensor open circuit GO to DTC B1251.
B1253 030 N/A A/C in-car temperature sensor short to ground GO to DTC B1253.
B1255 041 043 A/C ambient temperature sensor open circuit GO to DTC B1255.
B1257 040 042 A/C ambient temperature sensor short to ground GO to DTC B1257.
B1261 050 052 A/C solar radiation sensor circuit short to ground GO to DTC B1261.
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.

Good luck!

i tried this and at the end of test all functions light up and 888 in the center