1991 Mercury Cougar blend door actuator

Vincent answered my question about Error code E7 on the temp readout. I removed the blend door actuator and checked the motor and mix door. The mix door moves freely and If I use an outside power source the motor works. However, if I connect the blend door actuator to the heater connection, the actuator does not work. I have 4 volt reading on a meter connected to the heater connection that does not change when I activate the controls (heat, vent, defrost). Would the problem be in the blend door actuator or in the dash control module.

Thank you
Norman