I'm not sure either and I haven't pulled it apart enough to check, but there is a line running from there to back behind the HVAC controls and ever since it was installed the defrost only stays on for 10 seconds which sucks in the winter.
Ill have to pull it off and zip tie it somewhere better. You mentioned the steering column but what about the aluminum bracket that right inside the access panel from the drivers door?
Lastly going back to the defrost I want to hook it up so I can activate it remotely when I remote start my car in the winter