Hey Guys.
300TDi cruise control never worked but was going to have a do at sorting it, any common problems with them I should know about?
Cheers

First check if the cables within the rotary coupling (behind steering wheel) are still intact, using a multimeter.

- remove the center airbag (if fitted) on steering wheel: 2 x torx/star screw from back of steering wheel, T25 or T30, can't remember. Unplug airbag connector.
- loosen then remove steering wheel center bolt : 19mm nut. Disconnect wiring to the horn and cruise control. Carefully loosen steering wheel so that the wires are not "pulled" if the steering wheel came out suddenly. Be careful when removing steering wheel from steering column, allow the cables to slot through the hole on the steering wheel, so that the rotary coupler remain on the steering column.
- remove the ignition surround: 2 x torx/star screw at bottom, T25 or T20, can't remember again. Disconnect 2 electrical connectors: 1 for horn & cruise control & 1 for airbag.
- you may now remove the rotary coupler, pulling straight out and test it with multimeter.

if rotary coupler not working fully, you may "attempt" to repair it or replace it.

Discovery Range P38 Rotary Coupler Casette AMR5631 on eBay (end time 14-Jul-10 22:12:57 BST)

I repaired mine by taking it apart, cut away broken/crushed section, re-solder back the cables, rewound it back into the coupler.

Saying all that, my cruise control is still not working, BUT, at least I have got horn now....!!!

Splits in the vacuum hose where it joins the various bits of the system are common.

The little compressor unit under the jack storage is next port of call