Pulsating heater blower question

rbade12 at aol.com rbade12 at aol.com
Wed Mar 4 13:57:06 PST 2009

I can't speak to your?blower issue,?however, I can speak to the replacement difficulty of the blower motor and/or the heater core. It's a tough job! If the heater core housing has never been out you'll find it glued down very well, perhaps the most difficult part of the job?was just freeing it up to get it out. Then, trying to wiggle?this big thing?out of a "no clearance to wiggle it out" situation. It is tough, but do-able, and perhaps a necassary job to DIY...I think a shop would charge a lot of dough to do it, if they'd even do it. There is a "steak knife" method to replace the blower only that involves cutting the housing open. I know little about it. If you do replace the blower I encourage you to pull the housing and replace that old heater core too...you know that sucker will start leaking shortly after you were to do the motor alone.??? 


-----Original Message-----
From: SAJanesick - Bellsouth <sajanesick at bellsouth.net>
To: 200q20v at audifans.com
Sent: Wed, 4 Mar 2009 8:34 am
Subject: Pulsating heater blower question

The problem car: 1991 200 20V TQ - 3B - stock except the IA III+ chipped ECU and 
034 silicon intake hoses

Unlike you hearty folk living up north (except on occasions like Monday - first 
measurable snowfall here in about a half dozen years), my AWD is rarely engaged 
save the occasional quick start in the rain.  However, I actually do use my 
heater/defroster regularly in spite of our more moderate temperatures here below 
the Mason-Dixon line.  The problem is after 223K miles, it seems my heating and 
A/C blower is protesting.

The blower is working, just intermittently.  Usually in the cooler months, I 
punch the econ switch and then vary air flow and temperature manually.  A few 
weeks ago I first noticed the problem only when making a right hand turns.  
Although the blower would seem to be operating while I was driving in a straight 
line, even the slightest turn to the right would result in a blast of air from 
the blower as if it were momentarily put on high.  Soon as I straightened out, 
the blower speed would go back to normal where it would stay until my next right 

The turns could be either something modest like entering an intersection and 
turning to the right, or something more energetic like taking a sweeper on a 
twisty back road.  However, sensitivity eventually increased to the point where 
I can simply be maneuvering in a parking lot and that will be enough to engage 
the blower motor speed change.  Also at some point, depending upon how level the 
cars is, the blower will occasionally pulsate while the car is stopped, sometime 
pretty rapidly - perhaps on 1 second cycles - between high and low until the car 
is moved.  Finally the symptom also started to occur while turning to the left.

I have done nothing yet in terms of diagnosing the problem other than 
demonstrating it to a cadre of mechanically inclined friends at a local garage.  
One guy thought it was the head unit to he climate control, I think it might be 
a physical wearing of the blower motor brushes that have lost conta
ct other than 
when pushed to the right or left through the efforts of G-forces, and another 
guy could neither hear nor understand the problem (we're all getting old and 

Mostly I'm just looking for either someone who has experienced like problem and 
can point me to a link or posting that deals with it, or someone who can at 
least confirm the identical problem and give me a rough outline as the to cure, 
or any other thoughts or ideas from enlightened individuals familiar with the 

Last but not lest, I have not yet worked my through the 82 pages of Bentley's 
VOL 2 section "D" diagnostics (O.K., 80 pages if you don't count the intentional 
blanks), thinking someone out there might save me a little time, but I'm not 
opposed to it if no one out there has anything to add.   

All help appreciated.  Until the weather warms up, guess I'll just keep trying 
to find the twisty way home.

            - Steve Janesick
              Oak Ridge, NC
              sajanesick at bellsouth.net

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