We purchased our 2016 F150 about 1.5 years ago. It has around 20k miles. We began noticing about 6 months ago that when it rains, one of the backup sensors goes off, even when nothing is back there, but the others don't. It's always the same sensor. I thought maybe it was rain, but wouldn't the other sensors do the same if so? Has anyone else had this problem? If so, what was it?

 

Had that problem on my 15, pull the plug, clean the connector and put waterproof silicon electrical grease on the seal. While you are looking at it verify nothing is cracked.

 

 

Me, too. Always the passenger side.