Hi, I've got a 2001 A4 Fronttrak and my heater blower won't shut off. A few days ago I noticed the heater blower was just blowing full blast, so I hit the off button to stop it but the blower won't shut off. I've tried changing temperatures but that doesn't really change the speed at all. As the car warms up and the cabin temp warms up, the fan doesn't really slow down. The only way to get the fan to stop blowing is to pull the fuse out.

I'm thinking there could be a relay that is stuck closed, but other than swapping relays out, not sure how to troubleshoot this. IS it possible to test the 2 blower relays with a volt meter to determine if they are stuck closed?

 

Never troubleshot that problem, so am not sure what you're looking for here, but this article will tell you how to pull a lot of info from the climate control. I assume it's gone goofy on you. Pay attention to codes 18 and 19 in particular.

AudiWorld Tech Articles

 

Same thing happened to mine, The button is stuck in. Did you spill anything on the control head? Do you have the cup holder at the top? I had to pull the control out disassemble it and wash all the coffee and crap off of the buttons. Once you get it out it's only a few screws hold the whole thing together. Mine was stuck on defrost at 63* In the winter. When I started the car full blast defrost. Cold *** air.

 

So I pulled the codes from the env control, and came up with an 18.1, fresh air blower static. Thanks for that link by the way.

I'm confused about the button being stuck in though, because the blower continues to blow even after I push the off button. Did you encounter the same behavior with yours when the button was stuck in? I assume the OFF button would override any other button on the panel being stuck in and would shut the blower off even if a button was stuck in. Or am I way off there?

Since it's continuing to blow even after the off button is being engaged, that's why I was thinking a relay is stuck closed. Could that be a likely possibility?

Just wanted to see if anyone else had encountered this problem and how they had resolved it.

 

I believe "relay" is a module that's built onto the blower motor. It's not just a resistor like the old systems, but some people still call it that. Check this out, scroll half way down:

OEM / Performance Parts for Audi, BMW, Mercedes Benz, Mini, Porsche & Volkswagen - ECS Tuning

But don't go buying a part based on this post. I'm still not sure what's going on. That "fresh air blower voltage static" code is a big clue, I'm just not sure how to nail it down without doing a buch of searching that you can do.

 

thanks mtroxel.

According to that resistor section from the link you included, the behavior i'm encountering with the blower stuck on high all the the time, even when off, indicates a blown resistor. I wonder if I could pull the blower out and test the resister with my multimeter, if that resister module is no longer an external component.

I've got the hayes manual for my car, so I'll dig through that to see if there are any clues as to where a resister may be.
Thanks.

 

Yea, the off button did nothing. Because the defroster button was pushed in. It's a PCB with those little tactile pushbuttons.

 

Oh, I didn't realize the off button did nothing. That's pretty interesting. Since the defrost button was stuck in, were you able to change where the air came out? In my case I an redirect the air flow while the system is on. When I hit the off button, it just blows out the floor vents. Were you also seeing code 18.1 on your env controls under the button stuck scenario?

So it seems it would either be the button is stuck in scenario, OR the resistor is blown. Since I'm getting code 18.1 - Fresh air blower voltage, static, that would seem to indicate to me that constant voltage is being supplied to the blower, ergo the resistor is blown.

 

No I had no control, couldn't turn it off or change temp, or anything. so yours might be a different problem.

 

Ok, thanks planedr65, that helps. I'll fiddle with the buttons, but if that doesn't change anything I'll pull the heater and see about testing/replacing the resistors.

Thanks again.