I have a '98 Discovery. TheCCis hit and miss. I have checked the vaccuum hoses no leaks. I installed a new dash switch and a new relay. I took it to a Land Rover specialist, not a dealer, and they told me it could be the CC ECU. I bought a used ECU on Ebay. I have checked the brake pedal switch and it seems to work okay. It is hard to get at the Vacuum Control Unit as it is somewhat buried. An suggestions on what to try next. Most of the time the CC won't engage and when it does it stays on for 20 miles and then it drops off and won'tengage again.

 

Well I have heard of this exact same thing happening beofre but unforutently the poster never reported the repair.

I do not know where you should go from here.
When you figure it out please post the fix.

 

I have exactly the same problem with my 97. I am still working on tracking down the problem. One suggestion that keeps popping up to make absolutely sure there are no vacuum leaks is to use some kind of sealant, probably silicone type, to seal all the vacuum line fittings. I have not done this on mine yet as I have not been home long enough to but as soon as I have time I will give it a try.

 

AK-Liquid tape, you can buy it at Wal-Mart, its like $4, it has a applicator brush and everything, that is what I used to fix my cruise control almost two years ago.
I just coated all the connections.

 

Thanks Spike. I knew I had seen it posted before but couldn't remember what everyone said to use. I'll get some as soon as I get home Sunday.