What's the "connection" between Hands Free Assist and the Trailer 4 pin Connector??

[2016 Edge Titanium AWD]

Hi,

 

This is one of those, 'If my wife had told me 4 months ago' I could have fixed it stories.

 

After fixing the Tail Lamp Assembly on the hatch of our '16 Ford Edge this weekend I discovered that the 'hands free assist' to open the hatch no longer worked. I knew it had nothing to do with the work I had just performed and with my wife standing there I said, 'Gee that's odd, the hands free assist isn't working'.  My wife said, 'Ya, it hasn't been working for me for months so I switched to the release in the outer handle'. ?

 

Perplexed, I hunted around under the rear bumper, but was unable to find the 'sensor' that caused the hatch to open when your foot waved in and out under the rear bumper. Wouldn't work on either side of the rear bumper. Then I noticed this small rectangular connector box next to the hitch receiver and I pulled the cap off. Green crustys and puss greeted me. Got some CLR and cleansed the area followed by some electronics parts cleaner to flush and dry it out. Once satisfied that the trailer 4-wire plug was cleaned up, I put some silicone grease (NOT DIALECTRIC GREASE) on the 3 female pins and the one male pin and replaced the cap.

 

Waved my foot under the bumper and the hatch happily opened. Success, but why??

 

Does having a trailer wired to the Edge disable the hands free feature, or was there simply a short through that copper oxide goo that prevented the sensor from opening the hatch?

 

Can somebody please explain the 'Connection'??

[omar302]

I am guessing that with a trailer hooked (connected) the hands-free function wouldn't work to prevent unwanted opening/closing of the liftgate. Hence the trailer wiring is connected to the hands-free function.