ok then

check these things

1 - the 40A power steering fuse located in the back panel area on the fuse board, it is a slow blow fuse, make sure it's not blown.

2- check for a small contactor near where the fuse block is in the rear panel, may have burnt up contacts in it also check for power to it.

3- then as edward said, check the brushes in the power steering motor, you can remove the small covers covering the brush area and check the brushes.

After this it gets more complicated by checking the encoder in the steering column and its circuit. That encoder is connected to a steering activator card that gets signals from the directional control, the contactor in the rear, key switch input and a pressure switch from the motor pump sensor switch. You'll probably need a manual to get the diagrams and voltage check points and specs to do this part.