You need to wait 30 minutes in order for it to work again? It won't work from a straight ignition cycle?
I used to have a weird problem, as I always leave my cruise control on, the light is always on. I used to find, when I had a highline TDI cluster (my car is a diesel
), that sometimes the cruise control would be on at the stalk, but the light would not appear on the dashboard and cruise control would not work.
To fix it, I just generally had to flick the switch a few times and cycle the ignition (literally just on and off, I could do it while I was driving in a straight line, didn't have to wait at all). It went through a phase of doing this regularly and then it stopped all together, until it then started to do it once every month or so.
Since switching to a highline GTI cluster, I've never had a problem.
Outside of verifying all of the wiring to the relevant modules, checking that VAGCOM has the relevant coding (surely it would, or it would not work at all, but just un-code it and then re-code it), and trying a different stalk, who knows?
Sometimes if you have a sticky brake or pedal sensor it can cause it not to work... as it would obviously cut cruise control out if you braked or went to change gear. Very rarely, and I mean literally twice and both times it was after a clutch swap, I was on cruise control, CANCELLED IT (didn't turn it off, as I said I always leave it on and just half-flick the switch to cancel) and then went to reset back to the previous speed, and it wouldn't work. After doing the fandango (I just braked a little and also pressed the clutch) it worked.
Perhaps try pinpointing exactly what fixes it, if possible.. whether it works after pressing the brake and clutch, or whether it's only when you physically turn cruise control on and then off again.. and whether subsequent turnings off and on have any outcome.
