2010 GMC Sierra B0021 Airbag Code: How to Locate and Fix Side Deployment Loop Resistance Sensor

Hello everyone, I recently purchased a 2010 GMC Sierra Crew Cab (4-door) with a 4.8L engine, which had been sitting for seven months before I acquired it. After installing a new motor, the truck started displaying airbag fault code B0021 — 'Side Deployment Loop Resistance Above Threshold'. I'm looking for guidance on where to locate the control sensor responsible for this code (specifically the side deployment loop resistance sensor) so that I can clean or dry it out. In the past, I've successfully cleared similar codes by cleaning fuses in the fuse box or removing a faulty plug connected to a device causing the issue. I suspect these errors are related to the long storage period and moisture exposure. Can anyone confirm if this code typically points to a sensor corrosion or wiring issue? If so, where exactly is the side deployment loop sensor located on a 2010 GMC Sierra LS? Any advice or troubleshooting steps would be greatly appreciated. Best regards, Terry D.