question about A/C & heat

[pooleo8]

Last winter we had problems with the EATC. With the heat on, it was blowing A/C. We would just go thru the buttons, on/off and it would put out heat. Today while having the A/C on Max, it changed to HEAT! Nothing I did would change it. After having the thing parked for awhile at the doc office, the air was working again.

Anythoughts on what causes this?

 

[walnuts4x4]

usually with not being able to control heat/AC it is a problem with the blend door... the stock door is cheap and the bottom hinge cracks and cannot move and when you drive it opens and closes.. affecting the temp controls... or the blend door motor might be going bad too...

 

[pooleo8]

Bump before winter! ***** getting cold out! lol

Upon further investigation, I believe the actutator and blend door to be functioning. You can clearly hear it moving. There is no snapping or cracking sound like if the stem of the door had broke off on the actutator. I swapped an EATC into my ranger, so I am familar with the blend door and motor. It really seems like the A/C just does not turn off??? If I start on MAX AC. then dial up the temp and change to VENT or anyother, there is ZERO change in the temp coming from the vents. Almost like its stuck on A/C. When I installed one in my ranger, I used the "rear wipe" (from an exploder) to turn off the A/C. So with that, I assume this head unit does this internally. Any thoughts...?

 

[pooleo8]

also, I tried the EATC self test, nothing happens. A dash circles one of the (8's) then the entire display lights up like it does when first starting the truck. Then, it just stays like this. I waited 15 min, nothing happened.

 

[pooleo8]

Well, Im guessing it is a blend door issue. Truck temp is 195. I have a mechanical temp gauge. Both heater core hoses hot. Rear heat blows good and strong. So, I guess I will tear into it!