Minivator 950 not charging?

We have a minivator 950 which we have installed it was working when we pick it up but we took the chair off and now it won't charge it was showing error code 2 for not charging i have stripped it down and looking down the track there is no brushes i've got to brass fittings with a square hole one for positive and one the negitive i take it the brushes just fit in to the brass units to charge the stairlift and we would need to get new brushes so could anyone confirm to me that it is the brushes and where is best tom order them from.

Regards