I have posted this on the Vectra C forums but I'm not getting any response as of yet so thought I'd throw it up on here as well. I have a 2002 1.8 16v Vectra C. Just recently (after converting my front cigarette lighter to a USB socket) my fan motor would only work on setting 4. Now I have come across this before and it was the classic windscreen wiper duct being clogged and thus water getting into the motor causing it to semi seize. Fixed this by removing the motor greasing it up and then replacing the thermal fuse. Thinking it was going to be the same thing I picked up a couple of fuses and then removed the resistor pack (fan is spinning freely by hand), put a multi meter across the pack and the fuse is fine. Wire the pack back in and proceed to switch the fan switch on and off to see if I can hear the relays clicking in, I can hear the main click in at level four but nothing for the other settings, then setting four stops working and I can tell that the fan motor is now permanently on at level 1. Anyone got any idea what's going on here, resistor pack gets really hot but then I've read it always does on level 1 and especially seeing as its not back in the motor housing being cooled.
Had this on my Corsa C apparently its a common fault, the resistor pack will just go on them, steps 1, 2, and 3 use a reduced voltage so the pack heats up. speed 4 is full 12V. Had two go on my old one easy enough to change thankfully.
Yeh I've fixed it before but this is a little different, starting to think its the unit in the dash with the knobs on.
Are you able to measure across the resistor card with it in place? Sounds like the switch might be stuffed it if it isn't your resistor.
