Steps were intermittent and worked when they shouldn't .... like when going down the road.....

I took the gear motor assm off , cleaned the armature and the brushes....lubed the end bearing, reassembled the motor ....tested.... ran one way then the other way using a magnet on the door frame..put gearbox back on steps...worked great except steps out with door closed and in when door opens.....removed and replaced gearbox numeous times with steps in various positions...no luck...finally just switched wires going to motor...works perfect now....how do I fix it right ?

You have fixed it right - probably... Later steps had the polarity switched, and yours may be a newer one.