Thing, I should have mentioned that my airplane is properly maintained and that I do all the preflight AP checks and set it up properly before I fly even if I have no plans to use the AP.
Generally on the 178 second thing - I would guess that 99%+ of the pilots who have killed themselves accidentally (or deliberately) flying in to cloud had a working AI on board.
Clouds'll kill ya - nasty puffy white b'tards!