To stop power going to the fan, pull the electrical plug out from the motor. It needs to work when you turn the switch to any setting except Off and switch on the ignition key. Unscrew the three screws, and gently lift off the blower motor cover. While doing this, push on the two plastic tabs to pull the cover apart from the motor. Take out the three mounting screws and lower the blower motor down gently from the housing. When installing a replacement blower motor, take the fan wheel off the old motor carefully, pulling out the push nut with pliers or a small screwdriver. Avoid damaging either the push nut or the fan wheel. Reinstall the nut by pressing it straight onto the shaft. We undo everything in the opposite way that we put it together. For Expedition and Navigator models, you can find a second blower motor in the center console. Start by loosening each screw and taking off the two metal supports underneath the console. Then, pry out the large duct from the blower motor and unscrew both upper and lower duct covers connected to the motor. Unplug the electrical connector from the blower motor and unscrew and remove its two bolts to disconnect it easily. Certain models have an external heating/air conditioning system added in the back, which you can access inside after taking out left-rear trim on older models or right-quarter factory-installed trim panels on newer models, making it simple to detach or test the additional blower motor.