I've been scouring for an answer but can't seem to find one. Hoping someone here can help. I just bought a used 2005 Lariat Supercrew and I noticed it had the reverse sensors on the rear bumper. I also noticed that they didn't do anything. In my search for answers, all I find are posts referencing a button. I went and looked...I have no button. Then I thought maybe they're not really sensors, but just place holders. Took a look under, and they appear to actually be sensors. They're all wired up and everything. So my question...what the duece?! I have sensors but no button, and no sound. Anyone here know what the story is and if it's possible to get them working?

BTW, this is my first Ford pickup (had a Ram years ago) and am loving it!