Hi. I have a 2016 Ford F-150 SuperCrew Lariat.

About 3 years ago, someone rear-ended me, and I ended up replacing the bumper, a few of the backup parking sensors, and the towing connector myself. I never did get the blind spot parking sensors fully working (and didn't care too much since I have a backup camera), but outside of that, I haven't ever had any other electrical problems.

Two weeks ago, I went over a pothole on a dirt road, and for some reason, that bump seemed to break most of the electrical systems in the rear of the truck. Now I have the following problems

• Cross Traffic System Fault
• Left Rear turn signal fails
• Right Rear turn signal fails
• No brake lights
• No backup rear light and no license plate light
• The electronic tailgate doesn't work at all (completely dead, so I can't open the tailgate).
• Blind Spot System Failure persists (I have had this problem for 3 years)

Here is a 2 minute video detailing the problem:
I looked under the rear for any noticeably faulty wiring, and I couldn't see any. I also checked some of the fuses...but I didn't see any faults (and I'm not sure if I'm looking at all the correct fuses as the manual is not very helpful particularly for the parking and traffic sensors). Disclaimer: I'm mostly a car mechanics idiot, so I probably haven't been looking in the right spot. If you can help me figure out how to identify the problem, I'd appreciate it immensely. Thank you!

 

So I decided to go digging under the rear of the truck again to see if I could find any severed wires or loose connections. Eventually, I found that the grounding wire attached to the grounding bolt (which attaches to the trailer hitch frame and the truck frame)...was slightly loose. Like 1mm loose. I tightened the bolt down...thinking that it could hardly make a difference...but low and behold...it DID! All of my rear electronics are working again (except for the aforementioned parking aid sensor(s) that stopped working 3 years ago). I feel like the grounding bolt is just barely threading into the truck's frame after having to pass through a hole in one of the trailer hitch mounting plates (an aftermarket heavy duty trailer hitch I installed last summer). I may go to an autoparts store and get a bolt that's 1/4" or so longer...because it may not be seating all the way to the truck's frame.

I just wanted to share my solution here...in case anyone else has any weird power issues in which many of your components stop working at once...Check that your ground wires are completely tight against the steel frame. Even if it's slightly loose, it may cause a total electronics failure in the rear.

 

Glad it was an easy and discoverable fix!
Thanks for the update..