With heat on in the discharge air will only reach 100° Clean heater core .

Hi Tom Thank you for your response Think I found the problem partially. I replaced the blend door actuator. I turned the temperature control to cold Watch the actuator drive to the cold side. Then turn heater control to full heat watch to drive little over halfway then the damper stopped. Unplugged the electrical connection to the actuator motor plugged it back in and the damper motor went to full heat 140 deg discharge . Cycled it back to cold worked OK cycled it back to heat it stopped the halfway again . Checked actuator door moved freely. It's like it needs to be programmed to drive open further or that temperature control Is bad. Any ideas?? can I clean the temperature Control .? Is it difficult to remove from the instrument panel . Whatever help you can give Is greatly appreciate it

If you search the internet you should be able to find removal and testing procedures for the control. Also try forums specifically for your car make and model. Tom