Problems with electric step

Auto Trail Cheyenne 660  2008.  Electric step deploys OK and if left for a while retracts with the remote, although sometimes you need to press the button twice.  It does exactly the same with the switch inside the door and when you start the engine it works but sometimes with a delay.  If you deploy and retract repeatedly it will attempt to retract and then stop at times.  Have removed rubber cover, cleaned and checked home switch which seems OK.  Cleaned all mechanical pivots, all seems free. 

I understand that this works off the vehicle battery, battery starts vehicle OK but is 9 years old.  When you charge the vehicle battery using the on board charger it charges to 12.4 volts but the other reading (I believe its amps) only goes down to 2.5, on the leisure battery it goes down to 1.4.  Could it be the battery?  Or does anyone have any other ideas please.