Apple MacBook Pro 17-inch (original, Core 2 Duo, 2.4GHz, Late 2007 CTO, Early 2008, and Late 2008) - Manual (Page 138)

MacBook Pro 17-inch (original, Core 2 Duo, 2.4/2.6GHz, 2008) Take Apart —Thermal Sensors 138
Bottom Case Sensor Location: MacBook Pro (17-inch)
Bottom Case Sensor Location: MacBook Pro (17-inch Core 2 Duo)
Bottom Case Sensor Locations: MacBook Pro (17-inch 2.4GHz
and Early 2008)