In order to read the sensor with the plug connected, you need one of these:
http://www.posi-products.com/posiplug.html
Or strip the vinyl off.
I can send you a few if you pm me your address.
The information on the second voltage test is very useful. It showed the DME was reversing the motor to see if the pin 4 changes state, appeared to be a servo setup, looking for a feedback signal.