AC blows from vent only/No vaccuum leak. Help!
 

2002 F150 Lariat CrewCab. Electronic climate control. Heat, defrost & vent work fine. When you turn max a/c on it only comes from defrost vent. Checked for vaccuum problem. Everythings OK. Someone said I need to replace the whole electronic climate control. They run about $500. Please tell me someone has run into this and knows a cheaper fix. PLEASE!

Except for the selection of the recirculation door, the vaccum controls should be exactly the same in MAX A/C as for VENT.

If the airflow selection is correct for VENT, then the EATC is likely bad.

Try running the EATC Self-Test as follows from the service CD"

l The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.

l 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.

l If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.

l 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.

l 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).

l 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.

l Always exit the self-test before powering the system down (system turned OFF).

l Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.


Let us know what the results are..

Steve

I have pretty much exactly the same problem, altough in any selector I put the fan, the air will always come out from the defrost, A/C, AC Max, floor, etc. Doesn't matter, it will always come from the defrost. Is there a fix for this problem?

Not at all similar.

SEARCH keywords "defrost vacuum" for multiple previous discussions.

Steve

So if my 02 F-150's A/C blows through the defrost when on max A/C and through the panel when I select Panel/Floor, the EATC is the most likely culprit?

If so, does anyone know if the EATC from a 2000 Explorer or Expedition will work in the F-150? It *looks* identical - same controls and all, but I don't know about the insides.

I see 3 different members have posted here with a problem - have any of you run the EATC self test yet? It would be advised that you do, and post the results as has already been asked. Make the computer work FOR you, that's what it's for.

You're absolutely right - I should have included in my post that the EATC test I ran gave an all clear and I still cannot locate any leak in the vacuum lines, which is why I was asking for clarification of the indications.

That said, can the EATC be bad without throwing codes? If so, can it be replaced with an EATC unit from either of the models I mentioned? Thanks for your help!

Sure. The EATC has no feedback mechanism for the outlet selection so there's no way it can know whether the system response to its command was proper.

Don't know. You'd be best to check with the local parts department to see if the part numbers are the same.

Steve

Mine not a vaccuum tube problem...
 

I had the same problem with the A/C blowing the defrost only. I searched high and low, all vaccuum tuvbes looked good. I brought it into the dealer for repair. They said the problem was the ATC assembly and I needed part #2L3019980AA automatic temperature control for $540!! Plus $200 in labor for a total of $740!! I said no %#@&%$% way!! I have fashioned a 1/8" steel bar with a handle that I push through the driver side vent to push the vent door open to allow air flow through the front panel. Anybody have any other suggestions?