On the way “home” tonight (to where I’m housesitting), there was a serious failure of the car navigation system, causing me to miss turns twice and go about ten miles out of my way. It probably would have been scenic if there had still been any daylight. I expect that it was just an intermittent failure, and the navigation system will likely be functioning correctly again tomorrow.
It’s not a factory-installed GPS navigation system; for the 2004 model year that was only offered in the Yukon Denali and not the regular Yukon or Yukon XL. So I can’t blame GM. Since I don’t have the GPS nav, I’ve been using an old-fashioned biochemical navigation system, and its processing power is divided among multiple tasks. Sometimes other tasks take precedence over navigation, though the scheduling algorithm seems to be nondeterministic.