EATC / Blend door problem

[Dharg]

Hi.

Had what I thought was the usual blend door problem - just cold air. So I followed the advice found on this site and cut a hole in the plenum with the idea of propping open the door. But the door was fine...it just wouldn't move.

I took it to my local mechanic (an ex Ford mechanic) and he diagnosed it as a bad control panel for the EATC. I bought a used one on Ebay and it solved the problem. All functions worked fine - for 2 months. Now same old thing, no hot air and the culprit seems to be the control panel again.

So my question: is there something else that could be damaging the control panel or am I just unlucky to have 2 units fail within 2 months? My mechanic says his experience is that these units are very reliable and in fact mine was only the 2nd unit he had seen fail.

Thanks for any help

 

[BrooklynBay]

Welcome to this forum! It's possible that the one from EBay might have failed with age. Keep in mind that it was a used part.

 

[JHC's Explorer]

I don't know what you mean when you say "control panel". The temperature selector is actually a potentiometer just like rotary volume controls used to be. That part, from Ford, costs about $15. I had one replaced about 4 times by the Ford dealer (I only paid for the first one - the rest were warranty). When I sold it, it was broke again and the new owner took it to a different Ford dealer that said the other dealer had been replacing the wrong part. I had the same scenario as you: replace the part, works a while, then broke again. Unfortunately, I can't tell you what the part was that was eventually replaced that solved the problem.

 

[rwenzing]

Besides the blend door itself, the weakest link in the EATC is the blend door actuator assembly that moves it. The gears inside tend to wear out/strip/jam because, unlike the manual Explorer A/C system, the EATC is constantly moving the blend door position to maintain the set temperature on the display. I have never heard of an EATC head unit failing but that doesn't mean it doesn't happen.

 

[daffy]

I don't know what you mean when you say "control panel". The temperature selector is actually a potentiometer just like rotary volume controls used to be. That part, from Ford, costs about $15. I had one replaced about 4 times by the Ford dealer (I only paid for the first one - the rest were warranty). When I sold it, it was broke again and the new owner took it to a different Ford dealer that said the other dealer had been replacing the wrong part. I had the same scenario as you: replace the part, works a while, then broke again. Unfortunately, I can't tell you what the part was that was eventually replaced that solved the problem.

I think you're referring to manual (knob) controls, DHARG has EATC, all digital.

 

[daffy]

Hi.

Had what I thought was the usual blend door problem - just cold air. So I followed the advice found on this site and cut a hole in the plenum with the idea of propping open the door. But the door was fine...it just wouldn't move.

I took it to my local mechanic (an ex Ford mechanic) and he diagnosed it as a bad control panel for the EATC. I bought a used one on Ebay and it solved the problem. All functions worked fine - for 2 months. Now same old thing, no hot air and the culprit seems to be the control panel again.

So my question: is there something else that could be damaging the control panel or am I just unlucky to have 2 units fail within 2 months? My mechanic says his experience is that these units are very reliable and in fact mine was only the 2nd unit he had seen fail.

Thanks for any help

Have you checked the motor operation? Could it possibly have a 'dead spot'

Try changing the controls, then 'helping' the door move, and see if it takes over from there, or fights you. If it ends up moving correcty, I'd say motor, if it fights you, it's some control related function.

 

[Dharg]

Have you checked the motor operation? Could it possibly have a 'dead spot'

Try changing the controls, then 'helping' the door move, and see if it takes over from there, or fights you. If it ends up moving correcty, I'd say motor, if it fights you, it's some control related function.

The control panel I refer to is the dash unit..showing temp etc. Have hooked up a separate motor (actuator) and it does not operate it either so am very confident it is the control panel. I will try another unit and see if it fails also then. If it does I will then know it is something else causing the failure.

About your thought on 'helping' the door move. When I first had this problem I tried to move the door by hand.It would not budge. But with a new EATC unit it worked fine...for a while.

 

[96eb96]

The control panel I refer to is the dash unit..showing temp etc. Have hooked up a separate motor (actuator) and it does not operate it either so am very confident it is the control panel. I will try another unit and see if it fails also then. If it does I will then know it is something else causing the failure.

About your thought on 'helping' the door move. When I first had this problem I tried to move the door by hand.It would not budge. But with a new EATC unit it worked fine...for a while.

Is the motor from another EATC car? The manual one is different.
dont eliminate checks of the wiring harness. Maybe wiggle some wires. Installing the new unit may have temporarily set the wires, and they moved back to their "faulty" position. Unusual(but not impossible) that two EATCs would suffer the same fate. Maybe the motor is shorting something out.