AC blower motor resistor replacement for 2002 F350
Some time back my AC quit working properly. I have the manual three dial AC (figure 1) and the fan
selector (4 speeds) only works in the last two (high) speeds regardless if it is set to vent, AC, or Max AC.
After some research on the internet I determined that there was a problem with my blower motor
resistor. It is located under the hood on the passenger side toward the firewall (figure 2). The Ford part
Number for this is 4C2Z19A706AA. The unit is held in place with (2) 8mm screws. You will need an
extension to get at it because there are some AC lines in the way. I found it easier to remove the
vacuum pump reservoir (figure3). It is held in place by (3) 7/16” nuts that are located under the wheel
well in front of the front shock (figure 4). You may also have to disconnect the lines running to it (they
should just slide off together). I had to hold the line coming from the AC compressor out of the way to
remove it. Once you have the vacuum pump reservoir out of the way and you remove the two screws
from the blower motor resistor you will need to disconnect the wires by releasing the tabs on each side
of the clip. Once you have it disconnected inspect the inside of the female plug for damage and/or
corrosion. If everything looks good you can plug the new blower motor resistor in and installation is the
reverse of removal. In my case the middle pin on the old resistor had corroded and it broke off and
stayed in the female plug of the wire harness. I had to purchase a new wire harness from the dealer
Ford Part Number 1U2Z14S411NA. When replacing the wiring harness be sure to take note of each
wires location in the plug as the new one may not be color coded to match. The one I purchased had all
black wires (figure 5). After making note of the wires and their orientation on the plug I cut them and
connected the new plug/harness (Figure 6 shows the layout of the wires in my application, however
yours may be different so you will want to verify it for your self). To make things easy I used quick splice
connectors and taped them up securely, however you may want to solder and shrink wrap or use the
connector of your choice. Once the new plug/harness is connected make sure the routing of the wires
do not interfere with any other components and you are ready to install the new blower motor resistor.
Continue the rest of the installation in the reverse of the order you removed it.
(Figure 1)

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(Figure 2)
(Figure 3)

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(Figure 4)
(Figure5)

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(Figure 6)

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