Backup Sensors Stopped Working ('10 Limited)

[qs933]

I have after-market (Echomaster) sensors on my '12 Limited -- had them installed by the dealer at the time of delivery. They are color-matched (black ones are about $100 less) with the "beeper" mounted in the cargo area.

Incidentally, the '14 Limited will have factory front and rear parking sensors. From the Toyota press release:

A front and rear clearance sonar system is standard on Limited models, and a rear-view backup camera is now standard on all 4Runner models. The system displays in the audio screen, increasing visibility at the rear of the vehicle.