heating problem

Customer Concern: HVAC. No hot air from the heating system. Has good temperature at the heater core. Tests/Procedures: Remove the temperature control, check the RD/WH wire for a 5V reference and the RD/LG for under 0.05V. If not OK, check the power at the blend door actuator on LB/BK and ground on BK. If OK, check again at the temperature control. Check the YW/LG for voltage to vary from 0.5V cold. to over 4.2V hot. If not, it has a bad temperature control. If it is OK, it has a bad blend door actuator or broken temperature door. Potential Causes: Broken Blend Door Defective Blend Door Actuator

check the Heating controls sometimes this unit goes bad once this happens no control over blower