Installed a new head unit with the PAC inverter. Also installed a backup up camera. Connected everything, but when the backup wire for the head unit is connected with backup wire for the PAC, the head unit will not function with the vehicle running. Disconnect that wire and all works well, just have to press button to get the camera to come on. Camera power comes from the tail light. Is there a alternate wire I can tap into to let the head unit know when I put it in reverse. My only thought is the PAC is designed for an automatic and I have a manual. My Jeep is a 2007 2 Door Rubicon.