My reverse sensors on my 04 (new body style) f150 stopped working. I have unplugged them and cleaned them ,but still not working. I have checked them by turning the key on and putting it in reverse with the parking brake on and all 4 sensors do make a fast ticking sound. The off light will not turn off. I Don"t know where the control module for the reverse sensors is or what it looks like.Ford parts says mine does not have a speaker assembly. Please help me with this! I think it is the the parking aid system module. Ford wants 216.00 for it. I have got to find it cheaper somewhere. The new part# is 4L3Z-15K866-AA. It is under the driver side dash,above the emergency brake bracket,on the back firewall. Mine has 2 plugs going to it. One plug is medium size, and one is small. It is about 2 1/2 to 3 inch square box with a small round speaker offset on it . It has 2 - 10mm nuts holding it on, one at the top and one on the bottom. Can anyone help with this in any way ! ! !

 

I had an issue with mine about a year ago. I do know if one stops working, the system as a whole goes into fault. They didn't work, the off light stayed on. Like a fool, I took it to the stealership. They got me for roughly $350 to change one of them out. They told me they had to test each one individually (which for some unknown reason took them two hours of labor despite them all being a plug and play device aka QUICK CHANGE) and then once they found the faulty sensor, replaced it (at a cost of about $175 on the sensor itself). I was pretty upset, but then again glad it was fixed. Then I found out if a sensor fails, it will almost always throw the code without a CEL, so a scantool would most likely find the issue and even tell you which one it is! Then I was even more pissed that the dealer made it to be some big deal to find the faulty sensor! Lesson learned! I know they are about $120 a piece, it may be worth it for you to buy one and keep swapping through until you find the dud. I know I would go this route if mine ever failed again. Don't need the dealer for anything other than buying the truck in the first place...and warranty stuff. Anyhow, It's Ford P/N 3F2Z15K859BA

http://compare.ebay.com/like/2709617...Types&var=sbar

Good luck