Buick Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry that you have not been helped yet. I just came online and saw your question.
If you havent gotten it yet, remove the lower trim panels at bottom of the dash and you can reach up from the bottom and get to the wiring harness to feed it out more to pull the climate control unit out more to access the connector and disconnect it
You are correct that those bulbs are not meant to be replaced but many people do. Unfortunately GM does not provide a part number, or even a wattage for them. The only thing I know is that they are small LED bulbs, but nothing else.