To address what you might be trying to accomplish:
* If you're referring to a "Change Oil" light: This light is usually reset manually through a sequence of key turns and sometimes brake pedal presses. The exact procedure varies slightly depending on the specific year and trim of your 2003 Explorer. Your owner's manual will have the precise instructions. Look for a section on maintenance reminders or the oil life system.
* If you're concerned about other computer functions: Changing your oil doesn't typically affect other computer systems. If you're having other issues, like a check engine light, you need to have the car diagnosed using an OBD-II scanner. Resetting any other computer functions without a proper diagnostic could cause more harm than good.
In short: There's no general "computer reset" button. Find the oil life system reset procedure in your owner's manual. If you have other issues, see a mechanic.
