2005 BMW Z4 Airbag Light

This client brought his 2005 BMW Z4 all the way from Olympia, Washington to have his airbag light fixed. I scanned the car and found that the airbag module was not communicating, after confirming power at the airbag module connector, I then exchanged the airbag module for a spare that the client brought, which did communicate but was too old to be coded to the car. I then disassembled the original airbag module to inspect the solder joints, and found nothing visually wrong. (This module was sent out to a airbag specialist and had some kind of software reflash done by them, but did not work in the car) I then put the original module back in, and it started communicating I can only conclude that there was some kind of corrosion or something else on the conector. The airbag light remained on so I rescanned it and found a 'knee airbag resistance too low error'. I then removed the knee airbag to confirm the error, it then came up with an open circuit. I inspected the knee airbag connector and found signs that it had been removed in the past, after reconnecting the airbag and resetting the codes the light went away.