Makes sense to me, except why the sudden engagement of the left front under load. It is totally unsafe, so the system isn't functioning correctly.

It probably thinks it is doing a good job. It reads whatever combination of inputs including the wacky input from the steering wheel position sensor, then does what it is programmed to do. Then it pats itself on the back.

These go out. It seems to be more often lately based on reported instances here. Makes sense since they're all getting older.

No issue, replace seat foam and covering, issue. This tech suspects the clock spring failed at the same time by coincidence??? One of the least failure-prone parts on the car?

The seat sensors go out all the time. I believe it is not a connector, and it is the sensor itself.

Overall, from what I can gather, diagnostics is turning into a lost art, especially at the dealerships. If the code(*) and manuals don't give an answer, many technicians are left guessing instead of thinking things through based on how parts work and interact.

Boilerplate: I am not saying all of them or anything like that, but an increasing proportion of them.

The Stability Control System probably thinks it is doing a good job. It reads whatever combination of inputs including the wacky input from the steering wheel position sensor, then does what it is programmed to do. Then it pats itself on the back.

If it were mine, I'd temporarily disconnect the steering wheel position sensor. This will cause the Stability system to go into an error condition but leave the ABS working. Now try the same conditions and see if the symptom is gone. If it is, then voila' you've probably found the problem.

Then replace the steering wheel position sensor, normal everything, and see what happens.

Let'* say you are taking one of these right turns, and the steering wheel position sensor gives momentary erroneous data that you steered left instead, it would be expecting that the left-front wheel would turn slower than the right-front wheel. Upon seeing that the left-front wheel is turning faster than the right-front wheel, it would say "gosh, it appears that I am yawing clockwise which is not what I should be doing based on the input that I see (improper left turn measured at the steering wheel position sensor), I should probably correct that situation because otherwise I will continue to rotate clockwise and then I will be sad and end up in pieces in a junkyard."

Then it applies some left brake to attempt to control the right yaw.

Then you straighten out the steering.

Then it says "good job, me, I see the steering wheel is at the straight position, and both front wheels are turning at the same speed. I get to avoid the junkyard a little longer! Woohoo!"

Thanks, I am going to tr disconnecting the steering wheel position sensor and give it a go. I really appreciate your sharing your thoughts and expertise. I agree that the mechanics of old with real diagnostic ability are going the way of the dinosaurs. Sadly, it run a quick code check and replace. No time to actually engage the brain module. Too expensive for the auto shop or dealer. Besides, just about any average idiot with a OBD scanner or better, and a box of decent tools, can replace parts. Sad to say. I will check back in after I have had time to try out this strategy. I also have to work on the other main issue I posted about and that is all over the car sites. That is my truck going into reduced power mode. You probably have seen my other post. Had the Throttle body replaced 3x'*, the TPS replaced, the fuel filter 3x'*, the fuel pump, The cable harness to the Throttle body replaced. My truck will shut down suddenly while driving, I pull to the side of the road dodging cars. Shut it down and 90% of the time, turn the ignition back on pump the accelerator pedal 5x'* fully to reset the computer oil life etc. and the truck will restart normally. It is a random occurrence but is happening more frequently now and is dangerous. I have read tons about the issue and it seems quite common. From Throttle body, to wiring to ground shorts, etc, etc, etc...

Cool, I'm curious how this comes out!

I understand that. We'll keep that discussion over there.