Radiator fan running at full speed (Golf Mk3)

I was in the believe this was an easy answer to search for, but no

Golf Mk3 Tdi, 1998.

I just change the front wheel bearings and everything around them. And when I started up the car the Radiator fan was running at full speed.

Can the A/C pressure switch force the fan to run at full speed? I did not run the car that long, but the temperature raised a bit, indicating that the temperature sensor was working.

So what can make the fan run at full speed?

under the coolant ball, there is a box with a fuse and a clear cover. it has a ton of wires going into it. this is your fan speed controller. it has failed. replace it with an OEM one for $120, NOT THE $30 on amazon. all the aftermarket parts for this are complete garbage and will not last more than a few days to weeks if your lucky. the reason? the clear cover has not been down or is missing. in the future wrap that cover up with black electric tape because its BS once that wire clip snaps off.