2006 K3500 ABS pulsing

[JohnC]

My Duramax did that. I recall there is a service bulletin on it. Problem was corrosion getting under the sensor mounting bracket and lifting the wheel sensor away from the tone ring.

Brakes - Bulletin No.: 02-05-25-008
https://www.tsbsearch.com/GMC/03-05-25-007D