Flew into San Francisco Airport late last night and had to rent a car and drive to a hotel – thankfully, not very far.

While still in the garage, I adjusted the rearview mirror so I could see out of it, then drove out into the dark to (eventually) find the entrance to Highway 101 South. It was only when I got onto the highway that I realized I hadn’t adjusted the mirror for night driving, and was getting headlight glare from the cars behind me.

On most rearview mirrors, you put your thumb in the middle of the mirror and use your forefinger to flip a little lever which tilts the mirror for night view.

On the Cobalt, this meant that my thumb landed squarely on the button which activates the OnStar system. The mirror view didn’t change, but the car suddenly started talking to me, a smooth woman’s voice saying “OnStar system activated.”

I have a horror of making unnecessary emergency calls, so I searched frantically for a way to turn the thing off, all the while driving 60 mph on a fairly busy highway at night – I wasn’t in an emergency yet, but I was about to be. Repeated button punching accomplished nothing. It wasn’t clear what the other two buttons on the mirror (one marked with a cross) were for.

Eventually I heard the voice of a live young woman echoing around the car. “Can I help you?”

“I turned this damned thing on by accident and can’t figure out how to turn it off!”

“I have to disconnect for you.”

So she did. I’ll bet she gets that a lot.

And I still hadn’t adjusted the mirror for night view. I finally figured out that there is a little lever, as expected, under the mirror, but you have to twist it sideways rather than flip it.

Argh. Just argh.