The power steering has gone out only when i turn to the left hand side in my 98 Cadillac DeVille. When i turn to the right, there are no probs. Leading up to the power steering going out, it became real jerky when i would try to turn, or when i was going down the street, it didnt seem like i could hold a straight line. I replaced the power steering switch, thinking it would fix the problem and hasnt. So.........how can you tell if your power steering pump is bad, or your rack and pinion, im leaning toward rack and pinion but definatly am not sure.... input please!

 

Since it was turning fine one direction, and not the other before it all went, my first guess would be the rack, and not the pump. If it was the pump I would think it would have issues turning both ways.