2003 Yukon Denali XL. I have had problems with the left front ABS brake only locking up due to the ABS system engaging during driving on off ramps and on ramps with the vehicle turning to the right and either decelerating or accelerating. I have spent thousands of dollars with dealers trying to sort out the problem. Nothing. I have replaced the ABS sensors on both front wheels, and this didn't help. the problem was intermittent for a long time, literally since 2005 and then became constant. I have now just pulled the fuse of the ABS system and drive without it. I have prior to this shipped my ABS control module out to a repair guy and received a refurbished unit. I reinstalled it and the problem still exists. Super frustrated. Any help with this from either mechanics or owners, would be helpful. I am thinking it'* a wiring issue.

Has the ABS module been flashed?

Wait, could you explain in more detail what the problem is? It looks like you're saying that the ABS is causing the left-front wheel to lock up, but ABS would never do that.

What codes are live right now?

I will have to again run codes, as I have cleared them after the reinstallation of the ABS system module and the problem continued, thus i pulled the fuse. And the short answer to you statement of the ABS wouldn't do that, sorry It does and has been a problem with the vehicle off and on since 2004. Everything under the sun has been replaced in the left front. At one point, the right front ABS sensor was replaced and the problem on the left front disappeared for several years. So sorry to say, ABS can and does do that. It is very obvious to feel the braking engage on the left front with the vehicle decelerating in a right hand turn off of an on-ramp or accelerating on to an onramp. As soon as the problem occurs, I have to take my foot off the accelerator and steer momentarily as straight as possible and it will shut off. That was the typical scenario, now it is happening in a straight line, thus the system now being disconnected.

It sounds like you're talking about the Stability Control system. Yes it uses the antilock system to inflict its will.

Has the steering wheel position sensor been replaced?

Interesting that you bring up the Stability Control System issue. I have seen the error light come on during the episode with the perceived ABS issue, however, none of the diagnostics have come up with a error code for it. Possibly because intermittent nature of the problem. I have seen the light come on in the dash periodically. To my knowledge, haha,,,the steering position sensor is probably the only thing that hasn't been replaced. That said, my most recent venture to the auto electrical genius, left me with a recommended replacement of the Steering wheel clock spring. The tech believes that that is the cause of another new issue, a Driver'* Side airbag sensor error. Which coincidentally occurred after replacing the driver'* seat form and covering. I was warned about this happening and that it is likely due to a bad seat connector. I have since removed the seat and checked all the connectors, cleaned them and reconnected them and nothing. The auto electric tech said it the steering clock spring. I thank you for your thoughts. So greatly appreciated. I am obviously a dedicated owner and loyal GMC guy.

The clock spring has nothing to do with your brakes. The light you see is the light telling you the stability system is being activated and then it applies the brake to the determined wheel to keep from losing control.
These dealers don't know how their systems work and charge you thousands of dollars so they can learn and never fix the problem you don't have. Tough lesson.

Ya, I didn't think the clock spring had anything to do with it but thought that I'd mention it. I think your insight, sadly is right on the money, regarding the Stability control system vs the ABS system. It totally makes sense to me, regarding engagement of the left front only while under load, especially while on a decreasing radius turn, either while accelerating or decelerating. So, the next step is? Wondering why the Stability Control System wouldn't create an error code? I am at a loss, and I greatly appreciate your time and input.

It worked fine. If it tried to apply brakes and it failed it would set a code of if one of the sensors fail it will code also.