Posted this last wk to Rennlist w/ no reply/help:

While driving to wk yesterday the fresh air blower fan kicked in by itself.

Even when the fan speed (control) is set to the off position it still blows, even higher. Was able to find the 40A fuse in the P compartment to shut it off since it would continue w/ the engine off.

Something def failed, sensor? Could this be COV related?

Any troubleshooting help w/ be appreciated. It's out of warranty now w/ 45K miles.

Thanks-

 

weird what did the dealer say?

 

Trying to do some basic fault understanding prior to getting help from a stealership.

Done some searching but can't find a similar state/condition anywhere.

There has to be something that failed leaving the fresh-air blower in the energized state.

 

Not sure how much trouble-shooting you can do in this situation.

For the speed control to be set to off and still the blower runs is a pretty dire symptom and suggests more than just a sensor problem.

The very few times I've had one of my cars in -- the Turbo -- for any HVAC issue (a rattle from I think an air control flap) -- my info is the HVAC system is a pretty sophisticated system. One benefit of this is it has some pretty good diagnostics and error reporting capabilities. Thus a tech with the right Porsche diagnostic computer could probably get to the bottom of this behavior. It wouldn't surprise me if he hasn't already encountered this behavior.

The only thing I have to offer would be to a battery disconnect, essentially a system wide power reset.

If you go this route be sure you follow the battery disconnect and reconnect steps in the owners manual. I'll hit some of the points: Turn off the igntion and *remove* the key. Turn off all electrical accessories. If any of the car's electronics options require codes to activate after a battery disconnect be sure you have the codes and know how to enter them.

After you reconnect the battery you should do an E-gas calibration. The steps should be in the owners manual. For my cars the steps are with one's foot off the gas pedal through the entire procedure with the key off turn the key on and leave on for at least 60 seconds. Turn the key off for at least 10 seconds. Done. The next time the engine is started the calibration process will be complete.

Reset the window limits. With the window all the way up press and hold the lower button until the window is all the way down. Release the lower button and press and hold the raise button until the window is all the way up. Continue to press the raise button for at least 5 seconds longer.

Repeat for the other window.

 

This is the part that fixed the problem:

2048707710 Blower Motor Regulator

Guy that runs the shop where I take my P-cars nailed it after I described the problem.

Thanks for the interest/help-

TT