98 ford windstar rear a/c blows hot air

my rear a/c blows hot air instead of cold air. Front a/c is fine with strong cold air, but when I switch on rear a/c, hot air comes out from the air vents in the rear panel always. How do I fix it? Thanks!

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macntx wrote:

In the rear heater\AC box there is either a heater control valve or a blend door, I don't remember which. In either case it is controlled by a vacuum signal from the front control head. The default position is full heat. Check the vacuum signal to the rear heat control device. The hose should be teed off of the front blend door vacuum line.
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I have a similar problem. It only happens when my 96 Windstar 3.8 is under load, i.e., going up a long steep hill. After the road levels out, the rear AC goes back to cold air. Do I have a mechanical problem with the heater control valve or possibly a general vacuum problem?
Thanks much for any info on this.
Gabby

the
blend door, I

from the

signal to the

door vacuum line.
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Gabby wrote:

Same problem. Also on most vehicles, the system turns off the AC compressor under heavy load. Your concern is probably vacuum though, since only the rear is affected.
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Thanks for the reply. I'll check it out.

under
rear
heater
compressor under

affected.
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