Well......................It's like the guy with the seatbelt.....It's not really supposed to. Though I'm sure if you googled long and hard enough, you'd stumble across something that you can share with all of us!
I grounded mine out and added a switch so I can have it legal for the inspections or grounded for using the navigation while driving. You cant input destination addresses or watch movies unless the brake is on so I bypassed that BS.
3 bucks for a SPST switch add it inline on the emergency brake ground wire, then run it to any ground spot under the dash out of sight but accessible to the driver.