[Vwdiesel] Heater controls

[Mary Beth and Chris Geiser]

Hi all,

The airflow control on my '92 Jetta Ecodiesel has stopped working.  
The top airflow direction lever will still turn the air flow off 
when all the way left, but in any other position for the selector 
lever the airflow only comes out the vents, no defrost airflow 
and no lower heat airflow.  This car has AC system.  I've read 
through Bentley which describes the vacuum system and servoes.  

Are there some common problems to check first?  A suggested 
plan of attack?  I have not yet verified that vacuum exists 
anywhere, but the brake booster still feels like its assisting, 
so I think the vacuum pump is okay.  

I will probably get to working on this tomorrow so I'm looking for 
any advise for where to start from an "ease of access" perspective...  
Archives talk a lot about Audi's climate control systems, but can't 
find any VW related discussions about this.

Thanks and a Happy New Year to all the smarter, better looking people 
out there.

Chris