Climate Control Malfunctioning?
 

Can someone please help me? My 05 Mazda rx-8's climate control system the heater control unit is not working properly. The left side knob for level of air works fine (1-4). The right side which is for the cold air or the heat is what's not working. If I hold the radio button and scan up once it gives me the temperature reading (1-16) on where the radio station channel appears. The temperature bounces around on its own. I have to slowly turn the temperature knob on the right and mess with it to get it to stay on the level I want. Do you guys know if this is the knob (which the dealer confirmed is sold separately on my model), or the HVAC actuator control arm, or the actuator itself in the glove compartment? Its definitely not the thermometer cause that was just replaced and this issue has been for a year now and better. Please advise.

Edit I figured it out! The Climate control system the heater control unit's knob potentiometer, there may be a loose connection in the Heater Control Circuit Board. Radio Unit has to be removed and the board connections need to be resottered.
Anyone know what causes this over time? No one goes back there.

It's a known problem with the circuit boards. There is a DIY fix in the DIY forum I believe