Can't switch ABS off

Hi guys, I need some advice please. According to the owners manual you should be able to turn the ABS off by turning the ignition on and then pressing and holding the ABS switch 3-5 seconds, whereafter the ABS Light starts flashing indicating that the ABS is off.

I can't seem to do that on my bike. What could be the cause of that?

I know the ABS is working on the bike, and the ABS light does come on in the instrument panel when starting the bike. Could it be that the switch on the handlebar is broken or dirty? How would I know?

Any advice is appreciated.

Thanks