Hi all knowledgeable people.
Regarding parking sensors (X350).
I have identified a faulty sensor (rear LH) not ticking, aware this may be the sensor or just the connection to it.
Question is: how difficult to access the wiring to check it out and if sensor is faulty, how difficult to replace?

 

plenty of prior posts on this subject, but the basic steps are remove rear bumper to access the sensor. The wire harness unplugs from sensor then twist a new one in. I purchased a used sensor from ebay for about $20 USD. Be sure to get the proper color. There are two styles...one straight and one 45 degrees...I believe the outer sensors use the angle sensor while the inner two use straight. Bumper removal is fairly easy. i added some steps in a post a few months back.

 

Great and thanks for the info, much appreciated, guess I'll be under the back end this weekend then.