Grand prix gxp low beam headlights won't come on

Do you know for certain they were both working before you noticed that they were both out? Check the bulbs first in case you have been running with only one light and you did not notice it. If not the bulbs, I believe there is a relay in addition to the fuse that may be the problem or, if not that then maybe the light switch itself died.

Yes they were. New bulbs and fuses. No relay #35 in the GXP. Still not working.

I received a letter about this. Your headlamp driver module. To correct you have to take it to a general motors dealer. Depending on the age of your car and number of miles will determine if they will cover the cost or not. But just so you know the part is around 300 dollars plus labor of course.