Your car has the Chrysler designed climate control system. It's controlled by a small logic board called the "amplifier"; the "servo" is the valve body for the heater, the vacuum flaps and, I believe the blower speed too. The amplifier in 123 and 116 models is located behind the glove box, I don't know about the 107.
If you determine that major repair is necessary you should take a look at the Digital Climate Control Retrofit Kit sold by performanceproducts.com. I just installed one last Friday.