Audi S1 Heater Fan Failure: Common Causes Revealed

I experienced a very similar issue with my 2015 Audi S3, and being someone with some experience working on cars, I initially tried troubleshooting the HVAC system myself. The symptoms were identical, complete failure of the climate control system with no air flow response regardless of settings. After basic checks of fuses and electrical wiring connections showed nothing obvious, I took it to a workshop. The diagnosis confirmed a failed blower motor, which is a common wear item in the air conditioning and heating system. The motor had seized completely, explaining the total lack of air flow. The repair included: Replacement of the blower motor unit, New cabin air filter (while they were in there), Recalibration of the climate control module Total cost was 365 Euro and took about 2 hours to complete. The system has worked flawlessly since the repair. Before suggesting specific fixes for your S1, could you share: Are you hearing any noise when adjusting the fan speeds? Have you noticed any burning smell from the vents? Did the problem occur suddenly or gradually? Have you checked if the cabin air filter is extremely clogged? This information would help determine if your issue matches what I experienced with my S3.

Thanks for providing those details. I had my last service just 2 months ago at 32730 KM. In my case, I noticed a faint humming sound before the cabin fan stopped working completely. This seems different from what happened with your S3, as my HVAC system failure was more gradual. The air circulation slowly became weaker over about a week before failing entirely. I already checked the cabin air filter and it appears clean. The electrical wiring connections also look intact from what I can see. No burning smells noticed at any point. Would be curious if anyone else has experienced this type of gradual heater fan failure rather than a sudden complete stop? The symptoms make me suspect it might be more of a control module issue than a blown motor.

Thanks for those additional details about the gradual failure, that definitely paints a different picture from my experience. In my case with the S3, the blower motor failed abruptly, but what you describe with the progressive weakening of air flow and humming sounds actually reminds me of a subsequent issue I had about a year later. That time, it turned out to be a failing blower motor resistor, not the motor itself. The resistor controls the different fan speeds in the HVAC system, and when it starts failing, you often get: Inconsistent air flow, Humming or whining noises, Gradual loss of certain fan speeds before total failure The repair was much simpler and cheaper than the full blower motor replacement, around 120 Euro including labor. The climate control system worked perfectly after replacing just this component. Given your symptoms are so similar, I would bet your heater fan issue is related to the resistor rather than a complete motor failure. This would explain why the air circulation decreased gradually rather than stopping suddenly like mine did with the seized motor. Would recommend having the resistor checked first before replacing the entire blower motor assembly. Much more cost-effective if that turns out to be the culprit.

Yes, the gradual failure pattern of my cabin fan does seem quite different from your initial motor failure experience. The way the fan speed controller gradually lost power over a week, combined with that humming noise, makes me think the resistor diagnosis could be spot on. The HVAC system behavior matches exactly what you described, first losing effectiveness at certain fan speeds before the air flow stopped completely. Since my cabin air filter is clean and the electrical wiring looks good, I'll ask the workshop to specifically check the resistor when I take it in. Really appreciate you sharing that follow-up experience with your resistor issue. Could save me quite a bit if that turns out to be the problem rather than needing the full blower motor replaced. Will report back once I get the actual diagnosis and repair completed.