Thanks to all of you for the help, really appreciate it. So.... I felt like to go to the bottom of this I had to do something I promised myself not to do again after replacing the heater matrix... I only had to remove a few trims though this time and got a access to it. Replaced it with the old one and got all 4 speeds working again! So that new one must be defective I guess. Case closed, up to the next ha haa. Cheers