Route the purple and black wires from the SOTF switch through the firewall to the fuel temperature sensor as shown in the pictures. Be sure to route the wires carefully, away from hot surfaces or moving parts. Also be sure to secure wires so they will not rub on any sharp edges.
Unplug the sensor and carefully cut back approximately 1.5” of protective wire shea-th ing. Be sure to not cut into the actual wires when removing the protective sheathing.
Insert pins into included plug. Press until you hear them click. Match purple wire to green wire. Then match black wire to green/white wire.
Uhhhg! I get it now - a little more information from the get-go would have been helpful and yes, I was conflating a 4WD switch with a tuner. One I have not run into yet. I usually see the type that plugs into the fuel rail pressure sensor - different animal. Thank you @GregWork
I see his dilemma if he is installing the switch in the link above - Ford changed the color of two of the wires for that sensor from the ones in the instructions for 2015-2019. He has a 2021 truck. Ford also changed the Fuel Pressure and Temperature SENSOR and when comparing the wiring schematics of the two, the sensors are wired differently and function differently and therefore wiring this switch meant for 2015-2019 model years will most likely not work as desired (if at all) and or set a code for the sensor and turn on the check engine light.
If you forge ahead and try it keep in mind that any damage caused from doing this is your responsibility. The best advice I can give is to contact the manufacturer of the switch and see what their technical support has to say. Again, a little more information about what product you have would be helpful. Do let us know what the result is. Good Luck.
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