Removal Procedure

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

Release and lift the windshield defroster grille from the I/P upper trim pad.
1. 1.1 Insert two small flat bladed tools, close to each other between the rear edge of the defroster grille and the upper trim pad near one corner of the grille.
2. 1.2 Begin to CAREFULLY lift the grille up from the trim pad.
3. 1.3 Work the flat bladed tools gradually to the other corner of the grille while continuing to CAREFULLY pry the grille up.
  
  Fig 1: Lifting Windshield Defroster Grille From I/P Upper Trim Pad
  Courtesy of GENERAL MOTORS CORP.
Lift the grille to access the sun load sensor, and/or DRL sensor, if equipped.
Rotate to release the DRL sensor from the grille, if equipped.
Rotate to release the sun load sensor from the grille.
Disconnect the sun load sensor electrical connector.
Remove the sun load sensor from the vehicle.

Fig 2: Removing Sun Load Sensor From Grille
Courtesy of GENERAL MOTORS CORP.