2000 9-5 Climate Control Problem

I have a 2000 Saab 9-5 which had climate control problem in the last few months. It started off with uneven heat on either sides. My mechanic replaced all three motors, including the distribution flaps on three different visits. The last visit was when he replaced one of those three motors. Then, the climate control unit, the one on the dash showing the display, had gone crazy. One moment it will be normal, the next moment, it will go dim and all symbols on the display show up. It cannot hold the settings on the control too. So at one moment the control can shift from vent to defog to heat randomly. My mechanic said climate control unit needs to be replaced. I want to know if other people has the same experience. Will replacing the climate control unit on the dash board fix the problem?
Thanks in advance for the help.
Andrew