Where can I locate the reset switch for the "service engine soon" light on a 2002 5.4? Thanks!

 

I don't believe there is a reset switch for the check engine light. You correct the problem that caused the light to come on and it will go away after a number of restarts.
Or, you can unhook the battery cable, turn on the headlights or attempt to start the engine and that will reset the computer.
The check engine light will be gone but if you in fact have a problem it will come back on.

Do a search for posts on resetting the computer.