Blower fan has a mind on its own

[simpson]

Hi guys/girls

I have strange problem with my heat blower fan, it randomly changes speed or even shuts down for a minute or two and then resumes at full speed etc... Sometimes when it stops, AC turns off also and then turns on when the blower is back to normal. Despite fan speed is randomly changing, nothing changes on AC display (i.e. there are 4 bars for fan speed constantly, AC is on etc.). Last year I have changed the resistor and that worked for only a month or two and now I have the same problem. Does anyone know what it could be the problem? I'm asking here because all garages here in Serbia are extremely bad, they're not commited to their work and interested in finding out what the problem is, so they will literally replace half of your car until they accidentally solve the problem.

Thanks in advance for your help

Forgot to add, car is Ibiza Mk5 1.4 MPI Style (make 2009)

 

[VeeFource]

We've had two mk5 Ibizas and both of them have mental blower control. Most of the time it's when you press the button and nothing happens at all, so you press it again and it goes up 3 or 4 notches in an instant. Sometimes it has to restart itself, ultimately I think the software it runs was written by Jane Austen.

 

[RUM4MO]

Maybe it is something simple like a problem with the fan motor itself? The brushes could be worn or sticking in the brush holders, or the motor shaft bearing is dry and seizes now and again.

Edit:- sounds like you had this problem, replaced the speed resistor and that sorted it for some time, now that same problem has returned? If so, was it a genuine VAG(SEAT) sourced part that was fitted, if not it could have been a bad one that has failed again - has the pollen filter been replaced or cleaned recently as if it is blocked/dirty it might be killing these speed resistors by letting them get too hot.