Ford 4W7Z-19805-AA Motor - Cooling Blower

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To check the blower motor circuit, start by inspecting the fuse and all connections for looseness and corrosion while ensuring the battery is fully charged. With the ignition switch in the run position and the transmission in Park, connect a voltmeter to the blower motor connector, and note the voltage readings as you move the blower switch through its positions. Changes in voltage should correspond to different motor speeds. The thermal limiter resistor assembly, located on the evaporator case in the engine compartment, contains three resistance elements for four blower speeds, with the high setting bypassing the resistors. Check the thermal resistor relay for damage and test the resistor block for continuity between all terminals.If the blower motor operates at only one speed, check for voltage at the motor, and if present, connect a jumper wire between the motor ground terminal and chassis ground. If the motor works, investigate the ground and re-test; if not, the motor may be faulty. If there's no voltage at the motor, check the resistor block connector for voltage, and if present at any terminals, inspect the resistor block and wiring between it and the motor for issues. If there's still no voltage at any connector terminals, check for voltage at the blower motor switch connector with the ignition ON. If no voltage is found, examine the wiring between the fuse panel and the switch. If voltage is present, use a jumper wire to connect the switch terminal with voltage to the terminals carrying voltage to the resistor block. If the motor operates normally, replace the switch. If the blower motor doesn't operate at any speed, check the fuse, and then, with the ignition and blower motor switch on, test for voltage at the motor positive connector. If there's no voltage, inspect the wiring between the fuse panel and the motor. If voltage is present, test the motor. If the motor works during testing, remove the heater control panel and ground each terminal of the blower motor switch connector with a jumper wire to check for proper motor operation; if it works, inspect the switch ground and replace the switch if needed. For switch replacement, remove the control assembly from the instrument panel, and then remove the screw beneath it that secures the switch to the main assembly.

Disconnect the blower motor electrical connector from the motor. This involves unplugging the electrical connector at the blower motor and using a voltmeter to test for power at the motor. Next, remove the cooling tube from the underside of the blower motor. Then, remove the retaining screws from the blower motor mounting plate. Turn the blower motor slightly to the right so that the bottom edge of the mounting plate aligns with the contour of the wheel-well splash panel. While still in the blower housing, lift the motor assembly up and maneuver it out of the heater housing assembly. If the blower motor is being replaced, the fan wheel should be transferred to the new motor at this time. It is attached to the blower motor shaft with a push nut. Grasp the nut with pliers and pull it off or get a small screwdriver under it and pry it off, being careful not to crack the push nut. To reinstall the nut, simply push it onto the shaft. Position the motor and fan assembly so that the bottom edge (the straight portion) follows the contour of the wheel-well splash panel. Maneuver the assembly past the wheel-well splash panel and into the top portion of the housing opening, then down into position. The remainder of the installation is the reverse of removal.

To check the blower motor circuit, start by inspecting the fuse and all connections for looseness and corrosion while ensuring the battery is fully charged. With the ignition switch in the run position and the transmission in Park, connect a voltmeter to the blower motor connector, and note the voltage readings as you move the blower switch through its positions. Changes in voltage should correspond to different motor speeds. The thermal limiter resistor assembly, located on the evaporator case in the engine compartment, contains three resistance elements for four blower speeds, with the high setting bypassing the resistors. Check the thermal resistor relay for damage and test the resistor block for continuity between all terminals.If the blower motor operates at only one speed, check for voltage at the motor, and if present, connect a jumper wire between the motor ground terminal and chassis ground. If the motor works, investigate the ground and re-test; if not, the motor may be faulty. If there's no voltage at the motor, check the resistor block connector for voltage, and if present at any terminals, inspect the resistor block and wiring between it and the motor for issues. If there's still no voltage at any connector terminals, check for voltage at the blower motor switch connector with the ignition ON. If no voltage is found, examine the wiring between the fuse panel and the switch. If voltage is present, use a jumper wire to connect the switch terminal with voltage to the terminals carrying voltage to the resistor block. If the motor operates normally, replace the switch. If the blower motor doesn't operate at any speed, check the fuse, and then, with the ignition and blower motor switch on, test for voltage at the motor positive connector. If there's no voltage, inspect the wiring between the fuse panel and the motor. If voltage is present, test the motor. If the motor works during testing, remove the heater control panel and ground each terminal of the blower motor switch connector with a jumper wire to check for proper motor operation; if it works, inspect the switch ground and replace the switch if needed. For switch replacement, remove the control assembly from the instrument panel, and then remove the screw beneath it that secures the switch to the main assembly.

Disconnect the blower motor electrical connector from the motor. This involves unplugging the electrical connector at the blower motor and using a voltmeter to test for power at the motor. Next, remove the cooling tube from the underside of the blower motor. Then, remove the retaining screws from the blower motor mounting plate. Turn the blower motor slightly to the right so that the bottom edge of the mounting plate aligns with the contour of the wheel-well splash panel. While still in the blower housing, lift the motor assembly up and maneuver it out of the heater housing assembly. If the blower motor is being replaced, the fan wheel should be transferred to the new motor at this time. It is attached to the blower motor shaft with a push nut. Grasp the nut with pliers and pull it off or get a small screwdriver under it and pry it off, being careful not to crack the push nut. To reinstall the nut, simply push it onto the shaft. Position the motor and fan assembly so that the bottom edge (the straight portion) follows the contour of the wheel-well splash panel. Maneuver the assembly past the wheel-well splash panel and into the top portion of the housing opening, then down into position. The remainder of the installation is the reverse of removal.