Hit with hammer to lever where the cable is attached.
Mostly cable are rost and need to be changed.
This is some general problem mostly caused by salt on the road in winter.
It can be when you have change the cable that you also need to remove the whole brake (rost) and add after wards to all moving parts some copper grease.
Bud to help you hammer will fit.
Bud then leave hand brake till you repair it.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix lorries/trucks.