so, i bought a 2005 lariat about 5 months ago, and the backup sensor have never worked right. when i get in and start the truck, the backup button will say it is on. as soon as i put it into reverse it will beep at me two or three times and just shut off (the button will light up off).
this really hasnt bothered me too much, but now i have a little time on my hands, so i was thinking about tring to figure it out.
any ideas out there???

 

I am no expert but I would check all the connections first make sure everything is connected properly. Faulty on/off switch? I am sure somebody will have an answer for you On my truck, if their is a little bit of salt/dirt on the backup sensors, it gives me a solid beep when I am in reverse. I am constantly cleaning them in the morning. Good luck!

 

I had the same problem with my 04 XLT, I checked and repaired the wireing harness at the back bumper ( in this rural area we do a lot of gravel driving and it had damaged a connector and sensor ). To fix it I went to a local wreaker and got an entire bumper off a wrecked Winstar for parts. After repairing the wiring and replacing the effective sensor it still would not work. In the end I actually had two bad sensors (not including the damaged one) that we only discovered by scaning with a computer capable of extended codes. If you know someone else with a working system ( trucks are easiest to access ) you could try a complete sensor swap, all 4 and see if that gets it working. If it does, I would put the original ones back in one at a time, testing the system until it fails again.

 

Had a similiar issue with my 2004 F150. System was working, I would put it in reverse, if there was something behind it, the system would chirp once and then turn off. Instead of pulling each sensor, I just put a garbage can behind one sensor at a time... each time the system chirped at me (indicating an object behind) indicated to me that this particular sensor was in working order. I identified the one sensor that was faulty which I replaced.