Air not blowing through front vents

Tiny
RED80
  • MEMBER
  • 2002 FORD EXPEDITION
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 11,400 MILES
The air only blows through the front defrost vents, the back air works fine. What could that be?
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Thursday, June 9th, 2016 AT 6:52 AM

9 Replies

Tiny
HMAC300
  • EXPERT
Check for a vacuum leak see picture and look at the vacuum motors see if they are getting vacuum when put on defrost/floor etc. It cold be a bad control as well.
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Thursday, June 9th, 2016 AT 9:52 AM
Tiny
RED80
  • MEMBER
Thank you. I will let you know what I get. I did look at the lines and did not see any broken or cracked, but I will go out and try to find the motor.
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Thursday, June 9th, 2016 AT 10:05 AM
Tiny
HMAC300
  • EXPERT
See if the motor gets vacuum, it may have easier access from driver's side.
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Thursday, June 9th, 2016 AT 12:23 PM
Tiny
RED80
  • MEMBER
Okay sir I see the motor now how do see if it is vacuuming?
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Thursday, June 9th, 2016 AT 12:56 PM
Tiny
HMAC300
  • EXPERT
Turn the air conditioner on or what ever is not working and pull line off and put your finger over it to see if it has vacuum if it does then reinstall line to see if vacuum motor will move the door.
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Thursday, June 9th, 2016 AT 3:50 PM
Tiny
RED80
  • MEMBER
Okay I turned the air conditioner on max and I pulled this line off (skinny yellow one) and it has really good suction (vacuum) I also put it on defrost and still really good suction. Still no air coming through vents only defrost vents on top of dash.
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Thursday, June 9th, 2016 AT 4:21 PM
Tiny
HMAC300
  • EXPERT
Make sure to see if the vacuum motor is working the linkage or it may be a broken door and not moving.
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Thursday, June 9th, 2016 AT 4:46 PM
Tiny
ELIZABETH GALE PATESEL
  • MEMBER
I have a 2003 Grand Cherokee Laredo. The air conditioner blows cold air but switches from front vent 2 floor 2 defrost vent simultaneously. None stay on very long they just keep switching back and forth. Do I need to get AC checked or what?
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Sunday, June 18th, 2017 AT 6:42 AM
Tiny
KEN
  • ADMIN
Hello,

This sounds like a problem with the automatic zone control has gone bad and needs to be replaced. Here is a wiring diagram (below) so you can see how it is wired.

It might be good to check the ground wires for the system and the fuses.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please let us know what happens, we are interested to see what it is.

Cheers, Ken
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Tuesday, June 20th, 2017 AT 10:35 AM

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