GMC Repair: Bonneville Dash Lights, gm service manual, windshield defroster

Question
The Dashboard lights on my wife's 1999 Bonneville SSEi work only intermitently. Either the headlamp switch rheostat or the ambiant light sensor is defective. I lean toward the Ambiant Light Sensor because they rarely come on at night. I have the GM service manual and I can't figure out how to get to the sensor.  How do I get to the sensor?  

Answer
Hi
Here is the 3 steps per GM Service
1)Pry upward in order to remove the windshield defroster grille from the IP.
2)Disconnect the sensors, if equipped. Refer to Sunload and Twilight Sentinel Sensor Replacement .
3)Remove the defroster grille.

Defroster gille is just held in by clips
You may need a thin bladed screwdriver to assist in getting it up enough to put your fingers under grille.
Should just snap out from frong,  and lift away from Windshield from rear.
If in doubt, you may want to take vehicle to a repair shop and just have it diagnosed before spending money on part(s) you MAY not need.
I hope this helps
JUST advise from experience.
Good Luck
Paul