That's your OFF button for your ( Reverse Sensing System , RSS )
You can view the 2000 Ford Explorer owners manual online at :
www . motorcraft service . com ( no spaces )
Click on Owner Guides
( page 33 shows the Reverse Sensing System )
According to the Owner Guide that is the button for the ( reverse sensing system )
It will run fine on 87 Regular. My 2000 Eddie Bauer runs on 87 unleaded regular.
Bolted to the bottom of the engine
P255/70/16
I believe it is 21 U.S. gallons ( 79.5 liters )
On a 2000 Ford Explorer : The ELECTRIC fuel pump is INSIDE the fuel tank ( it is installed through an access hole in the top of the tank )
www . motorcraft service . com ( no spaces ) click on owner guides
Ford Explorer headliner replacement instructions check related link below.
The 2000 Ford Explorer owners manual shows : for the 4.0 L - SOHC - V6 engine ( Motorcraft FL - 1A oil filter )
locks out rear door window switches
www . motorcraft service . com ( no spaces ) Click on Owner Guides
It should be in the compartment that holds your jack, bold numbers stamped on a metal plate.