For the C-BEZ-VOL, Customer is to plug the passthrough harness to the back of the HVAC module that they install into the new C-BEZ-VOL.
Here is our Volume bezel. At the bottom you can see the passthrough harness.
Here is a closer look at the passthrough harness.
The passthrough connects to the back of the HVAC module pictured below with a red circle where to connect the passthrough.