Probably a stupid question...

[feral]

You have to hold switch for about 3 seconds then a ASC OFF illuminates in the cluster

[Frosty]

It sounds like an electrical problem, it shouldn't just come on by its own accord, and especially not when your headlights are on.
It's hard to say if it is simply the cluster icon that's activated or the actual ASC system that's activated (deactivated actually).
I would have it looked at for sure.

[Syke]

the way it has always always worked for me is i need to be in a parker position and the button help in until the ASC OFF comes up on the display. resets if you turn the ignition off

[Graham]

I think LED tail lights caused this issue or something similar, can't quite remember.

Mine randomly popped up once and wouldn't turn off, car off & on fixed it and never happened again

[Dire]

Yeah as others have said it takes about 3-5 seconds to switch off (it feels like forever, maybe you're not holding it long enough?), then it says 'ASC off' on your dash (no beep, at least mine doesn't anyway).
Then to turn it back on the button only needs pressing not holding. It also turns back on next time the car is started.

I would be getting that looked at immediately, thats pretty concerning... Perhaps it is just the button and not electrical.

The button is meant to be backlit with headlights on like all the other buttons and nobs on the dash, thats normal.

[Graham]

Do a bit of a burnout and see if the ASC warning flashes up on the screen, one way to tell if its on or not! Lol.

Best idea ever

[squala]

It could possibly be the brake pads. As the ASC uses the brakes themselves, there could be sensors triggering the light.

When have you changed them?

[cj_sx_2011]

haha, do a burnout and see if the light comes on lol. yeah holding the button in feels like forever before it comes up aye