Is this the classic blender door problem?

[greenbeanmtx]

I tried searching to figure it out but didnt find what i was looking for. When im using the a/c or vent if i get on the throttle about half way or more the air goes from the dash vents to the defrost vents up at the windshield. Then once im up to speed it comes back to the dash vents. Is this the classic blender door problem ive always heard about? Is there any kind of simple fix? Does it look like i get to pull my dash out ? Sigh.....thanks for the advice everyone.

 

[SHOtimer]

The blend door has to do with air temp, not where it is coming out of. Have you tried running codes on your EATC? IIRC, you are looking at a vacuum problem going to the EATC, because that is what it uses to switch modes, and the default mode is defrost.

Doug

 

[Shoaz]

Yeah, not to worry, that's not a BDA problem. That does sound like a vacuum related problem.

The BDA is insensitive to throttle/acceleration/etc., and controls the air temp. Typical symptom is that the system is stuck on full hot. They'll also do the "thump of death" where it whacks itself against the stop once every second for ever and ever.

 

[khanartist]

Sounds like your engine is pulling too much vacuum for some reason at higher throttle. Like it was said above, defrost is what the ETAC will do with "vacuum off". Check the vac line going through the firewall.

 

[greenbeanmtx]

Thanks for the advice guys. I went out and looked it over and dont see anything that looks out of the ordinary but i dont know where to look for vacuum lines and such. I ran the test that shotimes has and it came up clean and clear however ive also got another issue. When i hit the a/c button to turn it on i dont feel the compressor kick on and the air doesnt get any cooler. Then once im out and driving for a bit its like the compressor goes " oh yea i need to turn on" and then the a/c gets ice cold out of no where and i then hear the compressor cyclying like it should and theres no problem from there on out. Once it comes on like that as long as i leave the eatc with the a/c on i can shut the car off and restart it and the compresser work like it should. But as soon as i manually turn it off then thats when this starts to cool when it pleases thing begins. Its full of refrigerant so that cant be it. This car is very goofy. But i guess i should diagnose one problem at a time ehh? Is there any vacuum line in particular i need to look at?

 

[jedhead]

I have a simular problem. There is a door actuated by vacumn motor that moves the door that directs the air to either the vent or defroster. I think my vacumn motor is bad. From the pics in the Helms manual I will have pull the dash out to fix the problem. I am stocking up on stuff to do the work, because if I pulling the dash out, I am going to replace the heater core, all the hoses and the actuators. I only want to pull the dash once.

Bob

 

[I'll sho u]

there should be some sort of vacume canister to store engine vacume for the a/c heater system. On fords it is usually a round plastic ball about 4 or 5 inches across. It is probably mounted inside on of the front fenders. It must be hooked up.

 

[Devin]

I agree when pulling the dash out to replace everything. I replaced the heater core, the blower motor the blower measurer dealie and I would have replaced the BCM but I couldn't find a replacement for my 90. Also resealed everything and replaced all the nasty screws.

 

[jessemachone]

yeah, im pretty sure it is in the right front fender... don't know much about the rest of your story so good luck.