I just bought an 02 GC overland and whilst the car is fine I get nothing from the reverse parking sensors. No LEDs, no beeps nothing. It's a genuine jeep system and I have the installation manual according to which it should have two supplies when in reverse. Both supplies are present as should be but still zilch! There's a strange Bosch thing that looks like fuse but seems to be a 240 ohm resistor. This also checks out at 240 ohms and carries 12 volts each side. All earths seem to be present and correct. Anyone had similar? Any ideas?