Air Bag*
Picture Bump.

Picture Bump.
This happed right after (same day I think) we got the car back from the dealership and were told the window switch in the car needed to be replaced.Dealt with that problem a couple of times. Replaced the airbag module in two cars and that fixed it. It's just forward of the backseat ashtray under the armrest/drink/changeholder.
If you do this, and the fault exists in your car, you risk setting a code on his Air Bag Module. When you put his module back in his car, the code will still be there.Also, did you reset the light after changing the module or did it just go away? (I might just try the module out of my uncle's car to see if that is what needs replacing.)