reverse park sensors

I have a problem with the reverse park sensors on my Freelander 1. When I put the car into reverse the orange light on the switch comes on, the buzzer makes it's normal sound for a fraction of a second and then it changes to a very high pitch for a second and then stops. The orange light keeps flashing and I cannot hear any sound coming from any of the sensors. Is it the ECU or the power supply to the sensors or something else? I swapped the ECU for a used one off eBay but it made no difference so either the replacement is duff or it's something else. Are the sensors wired in series or parallel?
cudley-d.

I think usually it's an individual faulty sensor. When you say you don't hear any sound coming from the sensors do you mean the beeping in the car or clicking from the actual sensors themselves?

cudley-d said:

Are the sensors wired in series or parallel?
cudley-d

Click to expand...

No. Each sensor has its own wires.