WARNING: This page is about a different car, the 2004 Subaru Outback, 2004 Subaru Legacy, and 2004 Subaru Baja. However, it is still accessible from the selected car via links, so may be relevant.
Open front hood.
Disconnect ground cable from battery.
Disconnect ambient sensor connector.
Remove ambient sensor from radiator lower panel.
Fig 1: Removing Ambient Sensor From Radiator Lower Panel