Freelander 1 Facelift FL1 stereo options?

SWMBOs new Freelander is here.
It's a year 2005 facelift HSE TD4.
It has factory reversing sensors. If I put the car in reverse and put my ear to each sensor I can hear all four making a ticking noise, but there is no audible warning of proximity.
My suspicion is that this is because a previous owner has changed the head unit. Do the reversing sensors feed through the head unit?
There is a six disc changer under the drivers seat and what appears to be an amp under the passenger seat. There is also a lump with wires going to it in the lid of the boot floor compartment which andyfreelander tells me is a woofer.
The doors say Harmon Kardon on them.
The head unit is an Alpine unit with a tray below it.
I am thinking that the best answer that will get the sensors, woofer, amp, CD changer all working is to go back to standard Freelander Harmon Kardon head unit.
Are there other options?

thanks

pscan.eu said:

Do the reversing sensors feed through the head unit?

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No. They have there own speaker in the RHS rear side panel, just above the wheel arch.

pscan.eu said:

standard Freelander Harmon Kardon head unit.
Are there other options?

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The factory HU was a basic Becker nav unit, but I think there was an Alpine option too.
If it all works, I'd be tempted to leave it.
If if doesn't work, it's best to fit a decent HU, and get that working with the amp and sub.
The speaker cone in the sub often fails, so will likely need replacing. There used to be a suitable driver available cheaply, but I don't think they'll available now.

Nodge68 said:

No. They have there own speaker in the RHS rear side panel, just above the wheel arch

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That's really useful to know. I will look into it. Getting the reversing sensors working will be a big win for SWMBO.

pscan.eu said:

That's really useful to know. I will look into it. Getting the reversing sensors working will be a big win for SWMBO.

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I've got the same issue on my FL2, where the PDC isn't working. I'll get round to it one day I guess.

pscan.eu said:

That's really useful to know. I will look into it. Getting the reversing sensors working will be a big win for SWMBO.

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Here's a link to the parts for that system Genuine Parking Distance Control ((v)from 4a000001) For Land Rover Freelander 1996 - 2006 Classic | Jaguar Land Rover Classic Parts

Does anyone have a wiring diagram for the PDC system? It might just be a broken wire or loose connector or something. The light comes on on the switch and sometimes flashes so I am hoping that there isn't too much wrong with it.