To reset the 2005 Mercury Mariner oil change light, please follow these instructions:

1. Turn the ignition to run (one position before starting engine).
2. Select the OIL CHANGE XXX% from INFO menu then press the SET control to access the system check function.
3. Press and release the SET control to display “OIL CHNG XXX% HOLD SET NEW”.
4. Press and hold the SET control for 2 seconds to display “OIL CHANGE SET TO 100%”.
5. Turn the ignition off and then start the engine to verify the indicator has been reset.