First, let me say that I have a Nissan factory wiring diagram that I'm working off of.The heater/ac fan doesn't work and there's no power to the AC switch. There are two wires at the blower motor. A blue and a blue and white. Ignition turned to Acc, fan switch is off. When the plug containing these wires is disconnected from the blower, the blue is hot and blue and white dead. When reconnected, both blue and blue/white are hot, and all four of the wires at the resistor are also hot. First question would be, doesn't the fan motor require a ground? The mounting screws are all rubber insulated and the blower casing shows no signs of any ground wire connection, either on the blower itself or the wiring diagram. I'm trying to work this problem one step at a time so I started with the motor
