Thread: Cruise Control

If you mean the cruise relay its located to the right of the steering wheel. Remove the cluster front surround and you will see it.
If you look on Rave there should be a step by step trouble shooting guide.
Start with the basics... is the Vacuum hose and diaphragm good, cable moving not seized ( located to the rear of the EAS box ) .

Well, I believe it is more than just a relay. From what I have read it is an ECU which is behind the Facia Closing panel.....wherever that is.
I have checked the other items such as vacuum hose etc and they appear ok. I can get it to work sometimes but it switches off by itself after a few minutes and then won't work until I try again a few days later.

I am sure we are taking about the same thing. Facia panel / Cluster surround.
Just take it off and you will see the relay

Are you talking about the instrument cluster?

Is it an aluminium case about the size of a cigarette pack?

rave says it is here

There is a relay and and an ecu. The Ecu is cig packet size.

See
022 P38 RANGE ROVER CRUISE CONTROL ECU AND RELAY | eBay

By the sounds of it you may also have a faulty brake pedal switch.

In the first instance you can reset it. If its still a problem you can replace it fairly easily.

If you are taking off the drivers knee panel and instrument surround anyway, you should at leat try resetting it. In my experience you may also need to take off the lower panel above drivers footwell, that has the cabin light mounted in it.

The switch itself is best described as a plunger. It is spring loaded and when the cruise control is operating it is the sensor that tells the system you have applied the brake. If its faulty it tells the system you have applied the brake even when you haven't.

Reach up along the brake pedal shaft until you can feel the top of the plunger. Push the pedal down a few inches so its out of the way. You need to pull the plunger out towards the pedal and then gently release the pedal and let the pedal push the plunger back to its "Start" position. It has a sort or rachet feeling to it, like doing up a zip tie.

This will reset the switch.

Replacing the switch is easy too, it has a sort of bayonet action locking it into place, and the vacuum hose attaches to the end of it.

Dave