Yep, that's not flashing codes. Somehow the computer isn't sensing that you've got it in test mode.
Here are some ideas. Note that I don't think any of this stuff should be unsafe, but that being said all airbag work carries the potential for accidental deployment and is AT YOUR OWN RISK. If you're not comfortable with that then don't proceed.
At the very least, don't have your wife in the driver's seat (like in the video!) or anything in the path of the airbag (raised seatback, tools, limbs) when doing ANYTHING with the airbag wiring.
1) With the car *off* and using a digital multimeter, check the ohms from that black wire to ground. It should be a good ground (basically the same as you get when you touch the probes together)
2) With the car *off*, remove the rear parcel shelf and
a) Check that the other end of that diagnostic cable is plugged in and tightly connected at the airbag computer (behind driver's seat)
b) There should be a separate ground bolt on the airbag computer. Check that this connection is good and makes a good connection to ground
Report back with what you find.