I have a 2008 F350. Recently, the rear parking alarm would go off every time it put it into reverse for a couple seconds and then turn itself off and could not be turned back on. After reading some of the forums here, I purchased a couple sensors and replaced two that looked bad. When I put it into reverse now, the rear sensor will now beep for about a half second, two to three times and then turn itself off again. All the sensors click when it is put in reverse. I was hoping someone on here may have some thoughts. Thank you all in advance.

 

Pokey - I don't have an answer for you, but my '12 F250 CC started doing exactly the same thing 2 days ago. First time I thought maybe a dog or something had gotten behind the truck so I got out and looked. 2nd time I thought maybe the lens was dirty so cleaned them. 3rd time I ignored it. That's how accidents happen.
I'm hoping someone has an appropriate fix to the problem.

 

If you put your parking brake on and turn the key to the on position and put it in reverse. Walk back to the sensors and put a finger near the sensor and you will feel a pulse. Thats is a quick test to see if the sensor is working.

 

Mine stays on a steady tone no beeps after I wash it or when the slush is caked up under the bumper. Once it dries its back to normal. Some day Ill get under it and check the connections I sure they are getting wet and shorting.