In this video I show how an air compressor can really help to identify the precise location of a rubber window seal problem. I also show how ordinary tape can be used to verify the location of the problem. (You can actually drive around with the tape too.)

This video was made while troubleshooting a problem with a Tesla Model X, but I've also done this with other cars.

I did this same thing years ago with an Olds Cutlass. In that case it had a whistling noise due to the way trim was mounted near the mirror. The "tape trick" identified the location, and the dealership then fixed the trim.