GM Service Manual Online
For 1990-2009 cars only

Object Number: 389846  Size: MH

The electrical auxiliary water pump (5) is mounted on the LH side of the radiator (3), which provides the additional flow of coolant across the radiator. This pump only runs when the key is in the OFF position, along with the electric cooling fan at low speed. The pump becomes activated when coolant temperature reaches 100°C (212°F) and shuts off at 95°C (203°F).