Random dimming lights

[Rylos]

I have a 2011 Yukon SLT 4WD and have noticed that randomly the lights will dim temporarily and then come back to full brightness. It almost always (99% of the time) happens as I am coasting to a stop, around 30mph. I also see it randomly at idle. Temperature does not affect it. I have seen it with the A/C disabled and the blower completely shut off. I can simulate the behavior by using the power windows, but I know these are a high draw item that will do this in a lot of vehicles. I had to replace the battery about 4 months ago and I went ahead and replaced the alternator then, but both of these did not help with the issue. I had read about a ground cable issue but I'm not to the point I want to start tearing into the thing yet to look at that. Anyone have any ideas? BCM? Bad ground? Gremlins?

 

[guy from norcal]

I get that every time i come to a stop too. ??