Yes, that would be the issue. The position sensor sends a signal to the EVO (Electronic Variable Orifice) which is connected at the bottom of the power steering pump.
It's a common issue with older Chevy trucks.
I also have a 1997 Silverado and it did the same thing when turning... scary around other traffic. I had a friend who told me that they are set up to turn in different increments depending on how fast you drive... so if you are taking a big turn at a slow speed it senses that and then you don't have to turn the wheel as much.. I didn't quite understand it, but he just went under the truck and unplugged a specific wire from the steering box... and it's been perfect ever since.
Where is the steering wheel position sensor located and how much are they to replace? I have a 98 Chevy and mine does it too, yet it's scarier due to my truck being jacked up! How are hard is it to change out this part? I have to get this problem fixed!
Sorry to hear your problems, for your sake and maybe for mine. Hope the same problem does not develop.
Basically I have the very same truck at the same 120k miles, but I've had it only two weeks or so. I was going to suggest that idler arm/idler arm assy. or tie rod ends could be a factor, but if the people working on your truck know their stuff, it's the first thing looked at and eliminated. Those very things I need to replace along with the pitman arm. However it is not giving me any steering problems at all.
Until I read the previous comments, I knew nothing of a steering sensor, to me it sounds like some gadget that's not really needed, but some elusive electronic device, there to fail and do just what it's doing to you. Causing you to return time after time, hopefully to a Chevy dealer to spend, spend, spend until you're at the end of your rope. Then as if by some miracle, they find this $5.00 part that cost you $2,000.00 to find.
Sounds like the other commentors have a good bead on the likely issue.
I am just another bleeding heart and soul brother in the family of Chevy owners. New to the group, yes, but already well broken in. Into my wallet that is. The bleeding thus far has been harsh, do I seem bitter? I should be fair though, I was told the timing chains are known to go 200k, that was the word of the guy towing it away, and after the DEAL on the repair - $1,162.00, what a deal! Oooouuucch... It was bad luck somewhat, the chain fell 80k short of its predicted life.
There's a list of things wrong, and it is likely to go near $2,000.00 to get it back to where it should be. Many things I knew about, and some were not told to me. The timing chain failure blows the budget big time. Sometimes you eat the bear, sometimes the bear eats you.
Hey, how 'bout some help here getting out of this bear.
Where's my Ford? Oh ya, in the drive way, blocked by the Chevy that won't run.