Cruise control fault Disco 2 Automatic TD5

[nigel hedley]

I have an 02 Discovery TD5 Automatic. Last week a fault developed that I am reluctant to share as it seems so ridiculous. When I am running on cruise control, and I turn my lights on, it drops out of cruise. If I switch the lights off it will not re-engage unless I stop, turn off the ignition, and restart. Any hints please

[lambert]

Bad earth?

[Range Rover Blues]

I'd need a wiring diagram to do any more than guess but it's going to be something daft like Lambert suggests, bad earth or something.  I'd be looking for any areas where the wiring loom is concurrent for both systems, round the dash/steering wheel area for example.

I had a lot of trouble with my cruise so I built a breakout tester for it, wired up LEDs to each input on the ECU and had them on a display so I could see when the inputs were working or not.  tracked it down to an intermitant fault on the gearbox switch which wasn't showin up on the engine ECU because it only happened when I was driving.

[mike142sl]

I have a sneaky suspicion it's something like that which is the occasional cause of mine dropping into Limp Mode after selecting reverse?

[JIMBOBLY]

not a rotten inner wing where the earth is attached is it,dont take it the wrong way,but i have come across it before