I have the same issue on my project P38, lovely hot air on the screen only, seem to remember from my last P38 there was always a "clunk" as the direction motor switched the vents. Not sure if I can be bothered to fix it at the moment, especially as the weather is getting warmer and still have a long list of mechanicals and MOT work? Lots of info on blend motors but nothing on the distribution side. I think my blend motor might be OK if I can change the temp but not direction, so might just be stuck flap?