2003 Buick Rendezvous Heating problem

Tiny
BIGJ1977
  • MEMBER
  • 2003 BUICK RENDEZVOUS
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 111,000 MILES
I have no hot air coming from the passenger side vents or the rear vents, a little heat coming from the drivers side vent and normal heat coming through the windshield defrost. The fans are working fine, the air flow is normal. Just no hot air on the passenger/rear side. Heat is on full. Have checked engine temperature and its normal as far as I am concerned, and I have checked the radiator full. I have posted this problem several places and no one seems to be able to point me in the right direction.
Monday, January 4th, 2010 AT 10:13 PM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Is the problem that there is no heat or the direction the heat comes out isn't correct, or both?

Joe
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Tuesday, January 5th, 2010 AT 1:23 PM
Tiny
BIGJ1977
  • MEMBER
  • 5 POSTS
No heat on the passenger side. Or in the rear.
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Tuesday, January 5th, 2010 AT 2:21 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If you are getting it from one place and not the other, you are looking for a vacuum leak. The vent doors that direct heat to different locations are actuated by vacuum. You will need to check under the dash for damaged or disconnected hoses. If you start the engine, you may get lucky and actually hear a hissing sound indicating where the leak is coming from. It truly can be a pain.

Let me know if I can help in any way.

Joe
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Tuesday, January 5th, 2010 AT 10:07 PM
Tiny
BIGJ1977
  • MEMBER
  • 5 POSTS
So just to be clear, I am looking for a vacuum leak. This vacuum helps shift the vents that direct where the warm air is going.
Now why is it that I have cold air blowing out of the passenger side? When I find and fix this vacuum leak and the vent door shifts, does the cold air get cut off and the warm air let in?
I am not trying to be a pain, I'm a mechanic on a submarine and just want to understand the system. I appreciate your help as you are saving me money that I don't have to spend on repairs.
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Wednesday, January 6th, 2010 AT 2:22 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Not a problem. I'm glad to help. As far as the vents, yes they run by vacuum. If the blend door or other door isn't opening or closing, you could draw cold air from one vent and warm in another.

Give it a try and let me know if you find anything. If you can't, I'll see if I can dig a vacuum diagram for the system.

Let me know.

Joe
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Wednesday, January 6th, 2010 AT 6:33 PM
Tiny
BIGJ1977
  • MEMBER
  • 5 POSTS
Well I found the problem. I started tracing vacuum hoses under the passenger side dash. (Not much you can actually see) They seemed fine, and couldn't hear any air noise during operation or starting the car.
I did however see a white plastic lever that was not connected to anything. Near it was a plastic pivot arm that had a "Y" shaped cutout in the middle not connected to anything either. These two fit together and apparently shift the vent door for the hot air. I now have hot air all around. The overall construction of how these two plastic pieces mesh together does not seem very good and I can forsee this happening again.
Thanks for you help, without your input I never would have looked under the dash. I had some "car guys" in another forum tell me it was probably air pockets in the heater core and that I should purge the air out and if that didn't work change the thermostat. Didn't sound right to me so I came here.
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Wednesday, January 6th, 2010 AT 9:36 PM
Tiny
BIGJ1977
  • MEMBER
  • 5 POSTS
Thanks again, left you some great feedback!

-Jason
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Wednesday, January 6th, 2010 AT 9:43 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
I'm glad you found it, and you are right, there isn't much room. Thanks for the positive feedback it means a lot to me, and let us know if you have questions in the future.

Thanks for using 2carpros. Com,

Joe
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Wednesday, January 6th, 2010 AT 9:56 PM
Tiny
LADYJ
  • MEMBER
  • 1 POST
I know this is an old post but it seems to be what I'm experiencing with my 2004 Buick Rendezvous. It takes forever to get hot it seems. Lot longer than it used to. And now today when it finally did get hot it went from hot to cold air a few times by the time I got home. The air flow is fine and is blowing at what would seem to be the appropriate speed for the level I have it on. It just started this a few weeks ago MAYBE. So the first of the winter season it was fine. I am NOT a mechanic but my husband can do a few things with cars and his brother is a mechanic by hobby. So is this other guy's solution something we should look into also?
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Thursday, January 19th, 2012 AT 1:27 PM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
Yes, LadyJ, it is.
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Sunday, January 22nd, 2012 AT 7:04 AM

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