Does anyone know the easiest way to run a wire from the engine compartment to the cab on a 2018 F-150? Thanks for the help !!!

 

If you're running only one wire there should be a few options on the firewall. Some people run the wire(s) under the cab and enter through one of several rubber grommets underneath. If you're running a 12 volt hot wire you need to take care not to allow the insulated part of the wire to rub against any sharp metal.

 

Thank you. It is the on/off switch for the light.