Well, I finally managed to replace that valve. I now get cool air from both sides (no more driver side always hot) but there is still some hot air out of some vents and only under some settings. With the vents set to dash, the two side ones near the windows blow warm, not hot. But when I switch the setting to floor and dash, all the dash vents are nice and cool, but the floor on the left hand side is hot, right hand side is warm and the back vents are warm. It seems as if the climate control module is having trouble controlling some of the temperature to certain vents. Now, as BRUTAL mentioned, when these heater valves go, they can mess up the climate control module, and I am doing the sat nav retrofit so I will be putting in a new one. Just wondering if anyone has any ideas of what this might be, or if a new module should fix the problem! I still may try the sensors since they are so cheap, and since I would be putting a new climate module in anyway, I'll see if that does it! Is it possible that there might be something wrong with the blend doors or something to that effect?
Thanks