My 1995 C280 has begun to make a very high pitched squeeling noise when the air conditioner or the heater is being run. The noise itself persists independent of the speed of the fan, but when you turn off the system altogeter, the squeeling stops. Through a search on the shop forum, I think I've isolated the problelm as having to do with the interior temperature sensor. (AllData refers to it as an actuator, I think) I copied all that AllData has to say on the subject but unfortunately there's not enough information for me to proceed without some guidance.

"The in-car temperature sensor with aspirator blower (B10/4) serves for measuring the temperature in the vehicle passenger compartment.
The in-car temperature sensor is equipped with an aspirator blower which continuously sucks air out of the vehicle passenger compartment for measurement of the temperature.
It is connected to the pushbutton control module by a separate electric lead.
The aspirator blower provides continuous circulation of the interior air around the in-car temperature sensor to ensure a high degree of control accuracy."

Can anyone tell me if it sounds like I'm on the right track? And what I need to do to repair/replace or otherwise fix the problem? I'm not a mechanic, but I am used to doing some of the simpler tune-up and brake repair type of jobs.
Thanks, Bob