Faulty Rear Perking Sensors Avensis Verso

[Tim P]

I have a 2002 avensis verso auto which I have owned from new. Recently the two central sensors have stopped working. The outer two are OK. I have tried swapping the sensors around but always the middle two don't work so I know it's not the sensor unit itself but something in the wiring.

When I put the car in reverse I get an intermittent beep with about a one second gap which is not usual (it used to only beep once to signify reverse and then only beep again if the sensors detect something)It's a repeat of the initial beep ie same sound.

I am guessing that the middle two sensors are on a different circuit to the outer two??? and the problem lies there somewhere.

Any offers. Thanks

T