Recently bought a RR Sport 4.4 V8 2006 which has cruise and ACC. Neither were working so I booked it into a garage for diagnosis. Various faults showed up and were cleared but still neither worked and ACC unit was apparently the problem. Eventually replaced ACC unit on front of car but still cant get cruise or ACC to work .
No messages coming up on dash.
I know Im an idiot but am I not activating the system properly ?
Can someone give me a step by step guide as to how to engage cruise .
Theres also the button on the dash above the radio which is lit and also the parking sensors one , a bit further along.
Iv tried following the manual but still cant get it to work.
Please help !!!

The ACC can be disabled, to see if it is a fault masked by the ACC, or whether it is a genuine issue.

9 times out of 10, it can be traced to a faulty steering wheel loom, or a brake pedal switch. Costs £15 each or so to replace

Also likely, but not as common would be a switch pack failing, or the clock spring behind the steering wheel

Thanks Mikey , will have a look at your suggestions and let you know the outcome. Ta Chris