So finally I've had some spare time to tackle this issue. I found out that a piece of white plastic normally connected to the back of the 'hot/cold' selector knob which connects the knob to the cable which moves the flap was snapped out of its place.
Important Information
Welcome to BRISKODA. Please note the following important links Terms of Use. We have a comprehensive Privacy Policy. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.