I replace the PS pump on mine for $140. Of course you will have to see which one you have and move over your parts.
That said, a quick check is to take the lid off and you should see fluid flowing back in the res from the return line. If that stops when you turn the wheel the pump or relief valve is likely bad. As in no pressure to the valve.
If not it could be the steering valve.
I found a gouge in the pump housing. A Cardone 96-6051 was a direct replacement. But I did have to come up with new o-rings for the output fitting.