A frequent question on the Difflock Discussion Forum is "Why doesn't My Cruise Control Work?" Even for the later 300tdi Discoverys the Cruise control was relies on a very basic vacuum system. A small hole or split in the tubing renders the whole system useless. Here's what to look for. . .

When the cruise control fails it can be any number of things. Electronics are usually at fault with most modern vehicles. Usually a simple switch or sensor has failed. With Land Rovers it is usually even more basic than that!

The photo below of the split vacuum pipes are not faked or otherwise tampered with, that is exactly how they were found on an eight year old vehicle with non-functioning Cruise Control. All of the electronics and fly-by-wire systems in this 300tdi Automatic Discovery count for nothing when a simple split rubber pipe can bring it down.

This is the most likely cause of the cruise control failure in this vehicle. The system requires a good vauum to operate. Split tubing does not form a very good vacuum!	You could go out and buy all new tubing but the simplest thing to do is just cut away the frayed ends and re-join to form a good seal

Although that might fix it there are other places to check for split ends and, thanks to Land Rover, they are not easy to get to:


The above photo shows the vacuum tube running down the left hand side of the vehicle just inside the wing. The Vacuum actuator is situated underneath the metal plate that the hydraulic jack is secured to (very handy!) The only way to access it if you don't have a very dextrous 3 year old child to help you is to drill out the spot-welds or rivets holding this plate and remove it.

You can then check to make sure the tube is firmly attached.