Mazda3Club.com : The Original Mazda3 Forum - Mazda3 1.6 2006 climate control full heat all the time

Hello, my girlfriends Mazda's heater is working splendid! (all the time ;)

In the garage they read fault codes B1261/B1282,B1283 and B1275 and are willing to fix the climate control for €900 so after some googling I ordered a replacement control unit from the scrapyard for €50 and she replaced it herself, unfortunately the problem is still the same.
She posted a cry for help on mazdaforum.com without any response and is currently wining at home and gave up.
Does anyone over here knows whats going on and how to fix it?
It's a very nice car and runs great but a repair half the value of the complete car is a bit much I think.

p.s. I posted this in 2 other forums, please don't be mad, I want to help her...