We were stuck in a 4 hour backup due to a fatal accident, and every once in a while, a light would flash under the passenger side glove box.

Saw an old thread about it possibly being the TPMS sensor. But my car's options list doesn't say I have it. I have the yellow TPMS light that comes on when I start the car, and the colored valve stem rings on the wheels but I see nothing under the dash (or in the boot, where I have seen it on other older DB9's) that looks like it would produce an intermittent flash, much less be a TPMS sensor.

Before I call the dealer, any other ideas what might be flashing under there?

 

That's where my display is! 2007 DB9. Under the glove box closer to the center of the car. I don't notice it often due to it's position. After airing up all your tires it might blink like crazy until it "re-reads" the sensors. It takes a few miles, then off.

 

If you have a light coming on on the dash, you should have the leds under the glove box. They're not easy to see. You really need to get down low to see them.

It's a pretty stupid system. So much better to just have the display tell you which tire is low. I think even Corvette has had this feature for years.

 

If the car sits idle for 15 minutes or so, the TPMS will go off.