HOTPOINT 9545 - No drum agitation?

Select a cycle. Water fillsmachine. Front cycle dial slowly turns as mchine goes through cycle. The thermostop(?)(with water tube leading into it) clicks. This cuases the commutator to SLIGHTLY move(clockwise and anti clockwise) but does not result in the drum rocking back and forth. However, if I select final 'spin' the motor/commutator spins as it should with lots of blue light from the brushes (brushes are brand new).
Is the problem:- (1)the motor is not geting enough ooomph input at drum rocking mode OR (2) the motor is fauty?
Any advise greatly appreciated