Ac fan

This is for hvac blower motor, if that's what your talking about? In the diagram, the top wire is voltage, the bottom wire is ground for blower motor. With key on and hvac controls turned on, use a test light and check voltage and ground for the blower motor, if voltage and ground is good, suspect a faulty blower motor. It might be possible to take electrical connector loose from blower motor, and use jumper wires from your battery for voltage and ground, to see if blower motor will run, use an inline fuse, 40 amp, just incase. I have seen faulty blower motors run intermittently, because of bad brushes.