DTC'S in PAM. Rear Park Aid/License Plate Lights. Please Help

[Akitahawks]

Thank for the ADD, been lurking but this is my first post. Using FORScan I discovered several Diagnostic Trouble Codes (DTC's) in my Parking Aid Module (PAM) and i get a "Check rear park aid" in reverse. Rear left inner/outer and right rear outer sensors have a "short circuit to ground or open" DTC. I replaced the right rear sensor to no avail, still had the DTC. Sometimes the sensors "tick" other times they don't. So, I believe this is related to my licence plate lighting problem, which is: I CANNOT get the lights to work. I have replaced the bulbs twice, replaced the light assemblies, and checked the fuses (the ones I think would be on the same circuit). There was voltage coming from the light sockets (the plug) the other day, now there isn't, but the lights didn't work either way. I mention the license plate lights because they appear to run in the same harness as the park aid sensors. Has anyone had a similar experience? Does anyone have a wiring diagram for those components? Seems to me there is an open ground somewhere but I would like to gather a little more info before pulling the bumper cover and exploring. Maybe a bad parking aid module? Does the module supply voltage to the license plate assemblies? Everything else works as advertised (trunk, stop, turn signal lights), and I have already checked all the connections in and around the area. Thanks in advance for any help!

2013 SHO, 79K miles, recently purchased

 

[Johnbigdog]

There is an inline connction for the bumper harness. Check this out. You may have to remove the bumper to find it?

Btw. The rear sensors (and front) may be the same part number. Call ford parts find out and swap them. Next time you won' have to buy a part.

Sensors not clicking makes me think missing power or ground. The P.A.M. won't get a singnal (0 volts) and set your D.T.C.

The parking aid and license lamps share c405. I bet the connector is your culprit.

 

[Akitahawks]

You nailed it Johnbigdog! Took the bumper cover off today and discovered the connector that supplies voltage to the harness was filled with dirt/rocks/mud. Have never seen one that dirty. This harness supplies power to the rear park aid sensors (4 each), the license plate lights, the trunk pop button (between the license plate lights), and one other sensor (?) I couldn't identify (I suspect it has something to do with the trunk release mechanism). The connector is located on the left hand side of the vehicle aft of the fender well inside the rear bumper. It is accessible with the bumper cover installed but I had no idea what I was looking for. Also the front and rear park aid sensors are not the same. Thanks for the assistance!