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Mike V.
Mike V., Auto Service Technician
Category: Car
Satisfied Customers: 23827
Experience:  25 years of experience, Certified Subaru Technician and Nissan factory trained.
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Why does ac come out of defrost and not the ac vents why moving

Customer Question

why does ac come out of defrost and not the ac vents why moving but stop and it does on a 1992 plymouth sundance? i moved the vacuum hose rite to the intake to make sure it has vacuum all the time still hasnt helped
Submitted: 1 year ago.
Category: Car
Customer: replied 1 year ago.
ive used two can of either trying to find vacuum leak. im a pretty dam good mechanic i thought but this has drove me nutts
Expert:  Mike V. replied 1 year ago.
Hi there,Which engine do you have in this car please?
Customer: replied 1 year ago.
2.5 auto no turbo
Expert:  Mike V. replied 1 year ago.
Ok, thanks.There is a one way check valve in the black vacuum line off the engine intake. If the valve isn't working, then when you accelerate and the engine losses vacuum the system will default to defrost, then when you let off the gas and it gets vacuum back, you start working right again. You need to replace the check valve with a new one, or find a ported vacuum source. It's kind of like the one way valve on the brake booster but much smaller. You'll notice that even when the engine is off, you get a couple of pushes on the brake pedal that feel normal until the pedal gets hard. There is a one way valve in there that stops it from losing vacuum as soon as the car stalls.Get a new one way check valve and it should resolve the issue for you.Please let me know if there is anything else I can do to help.What happens next:Just Answer will now charge you for the full amount of your question.My goal is to provide you with 5-star service. If you cannot rate me at least 3-5 stars, we will keep working on this.Just Answer does not compensate me for my time and effort; you do with a 3-5 star rating.
Customer: replied 1 year ago.
nope changed both check valves
Customer: replied 1 year ago.
theres one on the line going into the cab for ac and one off the spacer under throtle body going to the vacuum canistier
Customer: replied 1 year ago.
tieing that line going into cab for ac straight to the intake still lets it go to defrost sitting still!!!!!!!
Customer: replied 1 year ago.
you there
Expert:  Mike V. replied 1 year ago.
I am showing a single black vacuum line for the vacuum switch, however I am also showing 3 different 2.5 engines, do you know the 8th digit of the vin so I can make sure I am looking at the correct diagram please.
Customer: replied 1 year ago.
no its not here rite now
Customer: replied 1 year ago.
yes theres a blk line that tees off the brake booster line then goes into the cab rite above the gas cable. what r u callin vacuum switch?
Customer: replied 1 year ago.
can you call me
Expert:  Mike V. replied 1 year ago.
Sorry, I can't call because of hearing issues. It's why I do this online.The vacuum switch should be a block or the mode panel inside the car, all the vacuum lines should go into it them come off of there to the various controls.floor,defrost, and the vents. All are operated by the switch which should be the single black line into the car, then the switch should have a bunch coming off of it. It sounds like the switch could be defective and leaking vacuum. Default is the vent.Sorry about the delay, lost my internet there for a bit.
Customer: replied 1 year ago.
youl have to call me in bout 15 mins i have to leave the comp so if u will call me(###) ###-####bout 15 mins thanks
Customer: replied 1 year ago.
i no what your talking bout now no theres no switch theres a plug then they go to the switch. ill be bac to comp around 430 or so we can finish then thanks or can text me at***@******.*** in bout 15 mins thanks
Expert:  Mike V. replied 1 year ago.
Sounds good, I will be on then. It's been a few years for me since I worked on these older sundances.
Expert:  Mike V. replied 1 year ago.
Sounds good, I will be on then. It's been a few years for me since I worked on these older sundances.
Customer: replied 1 year ago.
r u still on
Customer: replied 1 year ago.
im sorry but cant see paying cause u have the same answers i do sorry to of takin up ur ti me
Expert:  Mike V. replied 1 year ago.
Are you telling me the switch inside the car doesn't look like this one on this site?http://www.auto-parts-online.com/products/87-95-a-c-heater-blower-motor-sw-chry-plymouth-hs226.html

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