Heater and air conditoner blend door problems

Tiny
MIKE LUCKEY
  • MEMBER
  • 1998 BUICK CENTURY
  • 3.1L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 150,000 MILES
Hi all, I have read a couple posts, but did not see my problem exactly. The air conditioner and heat wont blow out the vents in my car. The fan is running and a little air comes out everywhere. I replaced the blend door actuator and same problem. Also, the air conditioner wont work. The clutch is not engaging. I do not know if it is related or a separate problem. The wiring looks okay the compressor, and the relay is good (I switched it with the working horn relay) still no directed air. Any help would be appreciated. By the way, if I have an actuator, do I still have vacuum lines doing things? Also, it is dual climate control. Thank you.
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Saturday, May 21st, 2016 AT 6:30 PM

8 Replies

Tiny
WRENCHTECH
  • EXPERT
I do not know why you would change a blend door actuator for a problem with the mode door. The blend doors control temperature, not mode. There will be two vacuum mode door actuators on the left end of the HVAC housing. Check the vacuum supply lines coming from the engine and make sure that line is not leaking and has full engine vacuum in it.
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Sunday, May 22nd, 2016 AT 5:41 AM
Tiny
MIKE LUCKEY
  • MEMBER
Thanks I will check!
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Sunday, May 22nd, 2016 AT 7:28 AM
Tiny
MIKE LUCKEY
  • MEMBER
Can you tell me what the mode door actuator looks like?
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Sunday, May 22nd, 2016 AT 8:22 AM
Tiny
WRENCHTECH
  • EXPERT
I do not have one for your exact car, but here is a basic picture of what vacuum actuators look like. Your car will have two, one for defrost and one for other modes.

https://www.2carpros.com/images/external/HeaterVacuumActuators.jpg
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Sunday, May 22nd, 2016 AT 8:31 AM
Tiny
MIKE LUCKEY
  • MEMBER
Okay, thank you again. I will let you know how it goes.
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Sunday, May 22nd, 2016 AT 8:34 AM
Tiny
WRENCHTECH
  • EXPERT
It is possible for actuators to be bad but the more common issue is lost vacuum somewhere else, The best way to find this is to actually cut the line coming from the engine and measure the vacuum and then use a piece of tight fitting vacuum hose to splice the plastic line back together. There is a plastic vacuum storage tank that is also a common cause of lost vacuum.
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Sunday, May 22nd, 2016 AT 8:38 AM
Tiny
MIKE LUCKEY
  • MEMBER
There is a rubber elbow coming out of the firewall just right of center. It is attached to a half inch hard line in the fire wall and is necked down to a small size. There is nothing plugged into it. I am having trouble seeing anything dangling around. I will keep searching, seems like a likely suspect.
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Sunday, May 22nd, 2016 AT 10:05 AM
Tiny
KEN
  • ADMIN
Hey Mike,

Yes check the vacuum source to make sure the heater air conditioner system is getting vacuum at the selector valve behind the control panel, the valve itself can fall apart and you might hear a faint whistle.

Let us know what you find

Best, Ken
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Wednesday, May 25th, 2016 AT 12:24 PM

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