2004 Expedition Aftermarket Radio installed, no sound from backup

[JerrySmith]

Have installed aftermarker radio and not getting sound from backup sensor system.

 

[whtbronco]

I can't help but think you may have disconnected the parking aid sensor module or the speaker. I don't think it requires the stereo. I have an aftermarket head unit and I have eliminated the factory subwoofer and amp, yet my reverse parking aid still works. I really should unplug it, it drives me nuts.

Both the module and speaker are behind the left rear interior quarter panel. I think there's a good chance just by removing the rear driver side cup holders which pop out you might be able to see both. You can definitely see the speaker, it's in the right side of this pic from my stereo install between the fiberglass and seat belt .