cruise control stopped working - any suggetsions?

Any ideas gratefully received on the following:
- cruise control has stopped working completely
- vacuum on diaphragm on the engine holds fine
- no obvious cracks or problems with the hoses
- light comes on when switch is depressed on the dashboard
can anyone think of what to look at next?
Reply to
Thanks guys. My brake lights are ok; I just checked the switch under the brake pedal (have an auto box) and it's fine - delivers 12V from the fascia switch. Wondering now how to check the whole of the vacuum line whilst stationary and how the switching from the steering wheel connects up. Any suggestions?
Thanks in advance
Reply to
OK, I think I've found the problem. A 9 pin female multiplug with 6 active pins is dangling disconnected. It's under the steering wheel and I can't see what it plugs into.
Looking at the main circuit diagrams for 1990 model year RR, it seems certain that it's for the cruise control. The available cable doesn't seem long enough to get behind the instrument binnacle; though the wires have been previously bound up so it might reach.
Does it plug in there somewhere, picking up info from the speedo etc?
Paul 1990 US Spec RR V8 EFI LPG
Reply to
In message , paul writes
Think this one runs on an electrical vacuum pump located near side in chassis under where jack is stored. The pipe from vac pump is a possibility. Also upward stops for brake pedal are worthy of a check as when brake is depressed it allows air into system and disconnects cruise control. Vac pipe also to check from brake switch back to junction behind screen washer bottle.
Reply to
Richard Britton

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