take the steering sensor off the column ,the motor should go full speed. if not you may have a faulty controller which is the top part of the motor. only way to fix that is to replace it. hopefully you have already checked all the wiring between the column and the motor for kinks and breaks

Hi Edward the serial on the unit is G108V04548C. Thanks Pat

a serial number (series) would help in knowing what the possibilities are.
without a serial number I would guess you have a battery and battery corrosion problem. Pull the battery and get all the corrosion out from the area under the battery, and replace any power cables that have been sitting in the corrosion.
Also, while the battery is out, blow the motor and contactor panel clean.
also check the brushes in the power steering motor, if it is not an AC motor, and check the contactor tips