Parking sensor fault diagnosis - two light up and one does't
 

Howdy folks, I've got a 1998 320 where the parking sensors are fitted front and rear. The red LED light on the button for this system is lit. So if I try and press it, the front two displays will show two bars each and both red in color. While the rear distance display is completely blacked out.

Now this may be due to how I am parked in the garage, with distance to walls, but I wonder two things. One would be can anyone show/ tell me how the displays are supposed to look when they do work and no obstacle is close to them? I would imagine at self test / activation they would show two red bars and a couple of green ones. The ither would be, how to diagnose what is wrong with it. I.e. since the rear display shows nothing does that mean it is good or bad? I guess it is just a sensor or so that has gone bad. At least that is my hope so I dont need to locate new display or control unit etc. :-)


Oh and on pressing the button on the center console for the system a short beep is heard as well.

Thanks and an early wish for a Merry Christmas.

Put shortly, if anyone could share what their parking sensor displays are showing when they are working correctly and no obstacle is close? just to get an idea what is normal. Then I can go from there and fault check further.