Most times that is the result of a faulty blend air door actuator. The blend air door opens and closes based on if you are requesting A/C or heat.
What I'm going to suggest is this. Remove the actuator and see if it moves when you change from heat to A/C. Here is a link that shows in general how it is done:
Here are the directions specific to your truck for replacement. The attached pics correlate with the directions.
2005 Dodge or Ram Truck RAM 1500 Truck 4WD V8-4.7L VIN N
Single Zone/Dual Zone Driver Side
Vehicle Heating and Air Conditioning Air Door Actuator / Motor Service and Repair Procedures Actuator-Blend Door Single Zone/Dual Zone Driver Side
SINGLE ZONE/DUAL ZONE DRIVER SIDE
NOTE: The single zone heating-A/C system is equipped with a single blend door actuator. The dual zone system has two blend door actuators, one for the driver side blend-air door and one for the passenger side blend-air door.
Warning: on vehicles equipped with airbags, disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible personal injury or death.
1. Disconnect and isolate the negative battery cable.
2. Remove the instrument panel from the vehicle.
3. Remove the two screws (1) that secure the blend door actuator (2) to the back of the HVAC housing (3).
4. Remove the blend door actuator from the HVAC housing and disconnect the HVAC wire harness connector (4) from the actuator.
5. Remove the blend door actuator from the vehicle.
1. Install the blend door actuator (1) onto the back of the HVAC housing (2). If necessary, rotate the actuator slightly to align the splines on the actuator output shaft (3) with those on the blend door lever (4).
2. Install the screws (1) that secure the blend door actuator (2) to the HVAC housing (3). Tighten the screws to 2.2 N.m (20 in.lbs.).
3. Connect the HVAC wire harness connector (4) to the blend door actuator.
4. Install the instrument panel.
5. Reconnect the negative battery cable.
When removed, you will see a splined connection on the motor. Make sure it isn't stripped. Also, make sure the motor functions under a slight load.
Let me know what you find.
Images (Click to enlarge)
Sunday, December 20th, 2020 AT 10:25 PM