Max A/C setting not working??

[Bryanp66]

Hey guys,

I know its the dead of winter, but while I am getting things fixed on my truck. I wanted to ask about the max A/C. I have read a lot of threads about the broken blend doors, but my only issue is the max A/C setting. My temperature control works fine along with changes for defrost, floor, upper vents, bi level, and regular A/C. I get the same cold air out on max that I do on regular A/C. When it worked properly I could hear something under the dash change and the fan speed would pick up. When I switch from regular A/C to max there is no change. It is a 95 standard cab model. Any ideas???

Bryan

 

[UrbanRedneckKid]

It's vacuum actuated. It's located out in the open, right behind the glove box.

A/C max - Recirculate

Vent - fresh air

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[adsm08]

^That^.

 

[Bryanp66]

So then it would probably be either a problem with vacuum getting to the actuator or the actuator itself is bad?

 

[adsm08]

Or the door could be stuck.

 

[Bryanp66]

That's a different actuator than the one for the blend door right?

 

[UrbanRedneckKid]

With the engine running, and the switch to max A/C. Pull the vacuum line off the bottom of it, see if it's sucking. If you have a vacuum gauge, it should at least 13" of vacuum @ idle.

If so, make sure the door isn't stuck, and put vacuum to it, if no movement replace the actuator.

If no vacuum @ line, check for bad connections, and broken lines. Pull the panel, and check the back of the switch. Since it switches vent/def/floor position you know it has vacuum to the switch.

Let us know what you find.

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[UrbanRedneckKid]

That's a different actuator than the one for the blend door right?

Right. The blend door has an electric actuator. That's the one you read all the bad things about.

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[Bryanp66]

I will get on it in a couple days and I will be sure to follow up with you guys on it. Thanks so much

 

[Bryanp66]

I did notice something I forgot to mention. When I turn the switch to max ac I hear a vacuum hiss from the switch that sounds just like it does when you switch from one position to another, but it is steady and doesn't stop like it does switching from one position to another

 

[UrbanRedneckKid]

Probably needs a switch, or has a leak right behind the switch. Easy fix.

My old 98 had this same problem after I replaced a broken set of lines. Same symptoms you have now, it was the switch. Hurray for my 5 parts trucks!

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[Bryanp66]

I guess that part is a ford dealer item? Can you just get the switch or do you have to buy the whole panel?

 

[UrbanRedneckKid]

Dunno, and dunno. I got mine from one of my parts trucks, the switch is replacable within the panel.

Edit- Yup. Found it on eBay, $26. Not available through Rockauto. Only parts available are Motorcraft. At least that's what my quick search of the dub dub dub revealed.

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[Bryanp66]

One more thing before I dive into this- I don't have air coming out of the little vents to the left of the steering wheel and the one on the far right closest to the door. Is this tied to it as well?