I finally had time to do some tests and the weather was cooperating. It was a practically balmy 30F degrees outside. I tested the Blue and Blue/Red wires on the harness going to the ECU. They each had a constant 12V which they are supposed to have. ECU-B fuse is good as well. The door latches correctly when closing (meaning the actuator pulls in the door). I did a direct test on the actuator harness (Blue/Black and Blue/Red wires) and was able to open the tailgate with a power source. I tested the switch by unplugging it at the switch and completing the circuit and nothing happened. I am going to try to get another ECU to at least test. It's weird that this is the only thing that is not working for the ECU. My defrost and rear window both work correctly.