Followed manual instructions--assembly will not come free.
How to remove headlamp assembly to replace driving light bulb on 2006 Buick Terraza
I just changed the low beam bulb in a '06 Buick and found it really rather easy after researching it. I found no reason to remove the grill and the bumper cover, BUT you do have to remove the top 4 fastners that hold the grill assy to the radiator support, then you can work the headlight assy forward enough to work it out of the socket and turn it down so you can get to the bulb pockets on the back side. NO NEED to remove it all, just loosen it and gentley pry things forward enough to get the light assy out. ALSO> My supplier said his Wagner lighting book called for a 9006 bulb, but the car I worked took a H11. About 4x the money over a plain ol 9006 bulb but it might save someone picking up the wrong bulb. I hope this helps someone else out....Best of luck to you all