HELP Tahoe airbags randomly deployed

[Jsr86]

So I have a 07 tahoe with 94k on it and I was driving on a dirt road this morning and there was a dip in the road. I went over it and BAM! The freakin left and right airbag curtains deployed! I wasn't going that fast, just driving normally. Iv never heard of this before. I took it to the dealer and they won't cover it because its "out of warranty" and its going to cost $3900 to fix. How can this be out of warranty? It's obviously defective and should have never happened. It's never been in an accident that I know of and I did not hit anything when I went over the bump. Does anyone have any ideas on what I can do? I don't have $3900 to sell out for this. Do you think insurance may cover this, I have full coverage. Just trying to figure out what I need to do so when Monday rolls around and everyone is open I can have a game plan.