Workaround

This is a great unit for my 2013 Ford Mustang, BUT, the SYNC system needs to be disabled for the unit to work. Otherwise, the unit drains the battery.
The Metra instructions didn't work, so I contacted Ford and they said to pull the SYNC fuse. The fuse box is located near the passenger leg area and the fuse to be pulled is the 3rd one from the bottom (see diagram).