04 Air Conditioner question

[johng_22]

2004 Explorer Eddie Bauer 4.6L w/27K miles. Recently while driving my AC stops blowing out of the dash panels and begins blowing only out of the defrost when going up sharp hills. The air slowly begins to fade out as the truck pulls harder and I accelerate more while going uphill until it only blows from defrost. As soon as I have reached the top of the hill and let off the accelerator the air once again begins blowing out of the dash panels and stops blowing out of the defrost panel.

I've taken the truck to Ford once but the problem still exists. Dealer ran a vacuum test and claim they found a vacuum leak which they fixed. I still get a small sound from under the dash that sounds like what I'd imagine a vacuum leak would sound like that I only hear when accelerating. Unsure it it is related but I was told by the dealer that little sound under the dash is normal.

Anyone experienced or heard of this sort of problem? I'm planning on taking it back to the dealer but I'm afraid they're not going to resolve the problem since their 'lead' AC guy worked on it the first time.

Thanks in advance!

 

[shamaal]

The dampers on the first and second generation are controlled by a vacuum motor that draws vacuum from a vacuum reservoir. I suspect the same arrangement exists for the later models. On the early models it's under the hood, on the later models it's in the passenger compartment behind the right hand passenger kick panel. It's spherical with a couple vacuum lines going to it. This stores the vacuum so that when under acceleration the condition you describe doesn't occur. Either the vacuum lines have gotten disconnected or, more commonly, the reservoir has filled with condensation. Disconnect and shake out.

Someone else will have to confirm the location, mine's a '91. Let us know how it works out.

 

[johng_22]

Is it possible to do a visual inspection of the vacuum motor unit or is this something best left to the dealer?