1996 Honda Passport blower not working

I have removed the blower from the vehicle and tested it under a seperate 12V supply, and the motor runs fine. At the two-pin supply wire, from the vehicle, that feeds the motor, the Blue/White wire reads 12V available to the motor. I connected a jumper wire to connect the Blue/White feed to the motor terminal. I then connected a jumper wire to connect the other motor terminal directly to the vehicle frame. The blower motor worked with the engine turned ON, but without the ability to control it with the switch. My assumption is that a ground is not getting through the two-pin supply wire. My question is "why" and where do I look.