The water that flushes the softener into the machine is controlled by a solenoid valve (There is another one for fill and rinse etc.
Take the lid off and trace the waterpipe from above the softener tray back to the electrically controlled solenoid valve. Check the leads - if they are OK, dont try to mend it- it will only pack up again.
Go to www.espares.co.uk for spares and advice
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix washing machines.