Why A/C changes from Vent to Defrost???
Post Fiend
Joined: Apr 2004
Posts: 6,473
Likes: 4
From: Lafayette, IN
I just learned this not too long ago here myself..."Max A/C" doesn't blow any harder than "Normal A/C"--it's the same as "Recirculate" in all other vehicles, so you're not drawing in outside air any more on "Max A/C". The fan speed doesn't change, it just closes off the vent that allows outside air to come in the cab.
Jason
Jason
Junior User
Joined: Feb 2007
Posts: 91
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From: ida,va.
"the bomb"
Originally Posted by msb71
It never ceases to amaze how much this site helps people , just by reading this thread I fixed my Max A/C , it never blew harder than the normal setting did.I popped the hood and there it was, a dry rotted white hose, I fixed the trouble area using some hose I had laying around , and WOW! It blows harder now and doesn't cut off when accelerating, I always thought the motor shut the A/C off to save power for accelerations. Thanks a million!
Mike
Mike
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Joined: Mar 2005
Posts: 2
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A/C changes from Vent to Defrost
Hey Guys,
I don’t make comments on this web site because I don’t have the knowledge you guys have but there is one thing I can do and that is thank you for sharing your knowledge with people like me. You guys ought to get together and start your own radio show.
I was having trouble with my 98 Mountaineer switching from vent to defrost when accelerating. The air was cold but kept switching back and forth. I went to this site and started reading and learned of places or things to look for. I started looking on the riders side of the firewall for vacuum hoses. There is what I call a dash pot up there close to the hood hinge that should have had a vacuum line going to it. I started looking for a line and found that it had fallen down in the engine compartment. I just put it back on and she works beautiful. I had these visions in my head of having to tear my car apart to fix it but instead all I had to do was read and take your advise and I was able to fix my car. I know this is a bit long but I really thank you guys for your time and help.
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Mitch
I don’t make comments on this web site because I don’t have the knowledge you guys have but there is one thing I can do and that is thank you for sharing your knowledge with people like me. You guys ought to get together and start your own radio show.
I was having trouble with my 98 Mountaineer switching from vent to defrost when accelerating. The air was cold but kept switching back and forth. I went to this site and started reading and learned of places or things to look for. I started looking on the riders side of the firewall for vacuum hoses. There is what I call a dash pot up there close to the hood hinge that should have had a vacuum line going to it. I started looking for a line and found that it had fallen down in the engine compartment. I just put it back on and she works beautiful. I had these visions in my head of having to tear my car apart to fix it but instead all I had to do was read and take your advise and I was able to fix my car. I know this is a bit long but I really thank you guys for your time and help.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com
fficeffice" /><o></o>Mitch
New User
Joined: Aug 2005
Posts: 22
Likes: 0
Wow...my '95 F250 does the same thing. It switches from vent to defrost every now and then. I don't get home from Iraq until later this year but now know what to look for. I figured it was a vacuum problem but had no idea where to look.
Thanks,
Casey
Thanks,
Casey
Senior User
Joined: Jul 2007
Posts: 309
Likes: 0
From: Owensboro, KY
Aren't vacuum problems just great, guys? I don't know if this suggestion may help, but several of my K-car-based Chryslers had the same issue. Thankfully, the solution was cheap and easy. Chrysler came out with a small vacuum valve canister (it looks like and is the size of a 35MM film canister with ports on each end) that adds just enough extra vacuum reserve to stop the system from switching back and forth when it's not supposed to.
The part number is 4677204, and it'll only set you back $5-10 (depends on your local stealership). I've found it to be a big help on all the vacuum-actuated A/C units I've worked on, not just Chryslers.
The part number is 4677204, and it'll only set you back $5-10 (depends on your local stealership). I've found it to be a big help on all the vacuum-actuated A/C units I've worked on, not just Chryslers.
Last edited by jnewkirk77; Aug 18, 2007 at 09:54 AM.
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