Electric habitation step

Hello campers
Our electric step on our Lancasjhire 2011 is not working. Does the power come from the leisure battery or the main battery? If anyone has any idea how to solve the problem we will very much appreciate your help.
Thank you.

I'm guessing that in 2011 your Lancashire will have a Sargent electrical system in which case the step is powered from Fuse 5 in the EM50 Interface Unit, a little box of electronics and fuses possibly on the back of the base of the drivers seat.

Thank you Peter.  we will check it out in the morning and let you know how we get on.  Thanks for your help.
Kindest regards Jock and Evelyn Ballantyne