WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
Solder coated wire to ground
Harness protective tape
Intermittent short
Solder coated wire pierced through the insulation of another circuit.
Grounding foil
Fig 1: Identifying Electrical Short Inside Harness