2011 Navigator rear parking aid sensor issues.

[914rrr]

Having an issue with the rear paking aid sensors and occasionally with the fronts as well. Fronts get overly sensitive but then it works fine. Rears used to be intermittent but are now not functioning. Any test tips and parts sources would be appreciated.

 

[914rrr]

Anybody?

 

[914rrr]

I'm also curious about how new sensors should be painted to match the bumpers. My Nav is Pearl White.