Not sure it is the same issue but I had a problem when the car was almost new, the electric motor to lower the hatch only did not work every time. Dealer replace the latch/motor assembly, was ok for a few weeks then probleme was back and I didn't have time to go back so I remove the big bulk connector at the lartch and checked all female connection with a male connctor, 3 of them where not making a tight connection, fix them and never had problems fot the last 8 years. Signal probably come from body control module, next step would be to identify wich wireit is and test the signal.