The fan in my VW UP currently only works on full speed (4) and not any lower setting. It is an annoyance but not the end of the world.
Since today is routine annual service I asked if they can have a look at it while they have my car. £60 investigation fee. I don’t think they charged before to have a look, but ok. For that, all they could tell me was they want another £60 to take my glovebox out and poke around behind it. I told them no, as best case I can only imagine them charging yet more for replacing something expensive. I like a working slower fan speed, but not that much on a car that isn’t worth a huge amount and if more faults start appearing regularly might be time to think about replacing.
What I should have done earlier is Google the problem. It looks like it is a common thing on VW cars with the culprit being a resistor pack with a thermal fuse on it. I haven’t tried to narrow it down further for my specific model yet, but now I’m wondering how hard it is to access it and have a look myself. At least, I’m confident in electrical/electronics even if I don’t have tools from my former job at my disposal any more. If needed I might be able to bribe someone I know who still works there.
The service rep on the phone mentioned testing a fan controller. I now get the impression that the fan controller is literally the mechanical switch on the dash and a resistor. I dunno, for some reason I thought they’d do something smarter than that like PWM control which is much more efficient, if also more expensive. I think I answered my own question there.
Trade off as ever is how much is it worth my time to try fixing this myself vs living with my fan only being off or on hurricane setting.