I've read many posts on the horribly unreliable D1 cruise control scattered around the internet and mine is currently not functioning. I've just replaced all vacuum lines and it's still not working for me. I have no check engine light (I've read the system won't function if it's on). The next thing I want to try is replacing the switch on the dash - I'm thinking this could be bad along with half the other switches on this car. My question is, when the dash button is pressed, will the light on the switch (and presumably maybe a light on the dash?) illuminate even if something else is wrong with the system (vacuum leak or pump failure, brake switch, cruise control ECU etc...). After reading some other posts scattered around the internet, it seems that it should, but mine does not and I just wanted to confirm before I search for and buy a new switch...

 

If the light on the switch does not illuminate, the system will not engage. That switch can be cleaned out like any other. Just pull it out of the dash and follow the same procedures as any other switch. I believe I posted a guide prior to this in one of your other threads.

After that the ECU may be dead.

https://landroverforums.com/forum/di...rol-ecu-57040/