Rear Parking Sensors Not Working

[Sam5]

2003 IS Sport Cross  - 

66,000 miles  - 

6M  -  no satnav

Hi guys, long time lurker, first time poster.

I’ve got rear parking sensors that aren’t working properly after I washed the car.  I did NOT use a pressure washer.  But I did give the sensors a good scrubbing with a toothbrush to remove all the moss that was growing in them. 

They did work prior to the car wash.  In addition to the ‘reverse gear alarm’ going off, it used to be that when I started getting close to some large object with the rear bumper a second alarm would go off.  The beeping of this parking sensor alarm would increase in frequency the closer to the object I got.  Now, there’s nothing.  No beeping at all (except for the reverse gear alarm). 

Today, with the engine off but the key in the ACC positon, I put it in reverse.  I put my ear next to each of the four sensors and they are all making a clicking noise.  I put my finger on each one and I can feel it pulsating. 

Any ideas on what’s wrong?  Is there a fuse for the audible alarm that I need to check? I attached a couple of pics of the sensors.  I believe them to be original equipment. 

Thanks

 

[bobmc]

Once, when I took my car to one of those hand car wash places, one of my sensors stopped working after being subjected to enthusiastic power washing. 

I only noticed it at the time because they were walking around the car drying it and one of the sensors didn't beep. They gave it a quick blast with an air line and it has been fine ever since.

 

[Sam5]

I don't have access to an air line.  I sprayed them with a burst of compressed air in a can.  It didn't help.