1991 Buick Riviera broken HVAC

[Autry]

My 1991 Buick Riviera HVAC flap is broken the air only comes out from the defroster any fixes please help 9043700911 or email chubby91565@gmail.com

[Paul Dobbin]

If you can't get a new part, the You-Pull-It junk yards are lot of fun too.

 

Edited April 8, 2023 by Paul Dobbin (see edit history)

[dship]

1990-1993 Riviera and 1990-1991 Reatta use the same HVAC unit.  They can be found on eBay often, or as Paul above mentioned there might be one at a local (to you) pick n' pull auto salvage yard.  Hopefully you have a Factory Service Manual for your era Buick.  The manual shows how to remove and install a HVAC unit.

[Barney Eaton]

Are you sure the flap is broken? 

If you loose vacuum that allows the controller to change the output,  the default position is the defroster. 

I would check and verify that your vacuum hoses are good and not unplugged or cracked. 

The main hose comes from the top of the engine back to the firewall and there is a plastic T that is also a check valve. 

I have seen these "T" break and you loose vacuum to the controller. 

Another check is does your cruise control work.....   if the vacuum system is leaking the cruise will not hold. 

[Marty Roth]

14 minutes ago, Barney Eaton said:

Are you sure the flap is broken? 

If you loose vacuum that allows the controller to change the output,  the default position is the defroster. 

I would check and verify that your vacuum hoses are good and not unplugged or cracked. 

The main hose comes from the top of the engine back to the firewall and there is a plastic T that is also a check valve. 

I have seen these "T" break and you loose vacuum to the controller. 

Another check is does your cruise control work.....   if the vacuum system is leaking the cruise will not hold. 

I was about to add the same note as Barney -

It happened in two of our cars

[Ben Bruce aka First Born]

21 minutes ago, Marty Roth said:

I was about to add the same note as Barney -

It happened in two of our cars

 

 Yep. My 1992 Roadmaster same thing.  I had to change the vacuum " switch" in the control panel.  Real high tech!  Not.

 

  Ben