Should be a T-40 Torx bit.
On the brake pedal.
To change the thermostat on a 2002 Mercury villager, pull the hose away. If the bolts do not come off, wiggle the fitting to expose the thermostat to be able to change it.
1999 - 2002.
Brake light switch needs adjusting or replacing. It is too sensitive.
I looked at the Mercury Villager Owner Guides from ( 1996 , 1999 , and 2002 ) With engine oil filter change : Each Owner Guide shows ( 4.2 U.S. quarts )
You must remove the instrument cluster to do so.
There are two.
1999-2002 Villager or Nissan Quest.
Plug in a scan tool.
1999 - 2002.
Sitting right on top of the engine.
If it is defective it will need to be replaced.