So, this fix was based on repairing the BCM on my trans am a couple years ago. You can refer to that thread in the stickied section of the General Repair forum.

Both the ABS and Brake warning lamps were lighting intermittently and randomly on my 2004 suburban. I could never predict when it would do it or not do it:



So, what I figured was a bad electrical connection, similar to the BCM issues - cracked solder on the circuit board. TO remove the BCM, you have to find it. On the Suburban, it was above the driver side frame rail right near the sub-tranny. There are four screws that are a real pain in the butt to get to, best done with a torx bit driver:



There are three electrical connectors to remove and then the module comes out. Looks like this, and this should help you see where the four screws are located incase they are hidden like mine were:

 

Next, you need to use a razor blade to cut the lid off the module. It's glued on with RTV about 3/8" thick. There may or may not also be screws holding the lid on. There weren't on mine. I went around the perimeter a good 4-5 times cutting and then began gently prying with a screwdriver to expose more RTV and cut through it:



I immediately found several solder joints cracked - just like that BCM module!





I then quickly discovered that they used high temperature solder when they did these boards, and the 25W iron I had wasn't working, so I had to run out and buy a 125W gun. What you need to do is heat the joint and melt fresh solder onto the pins. If you try to melt the solder and let it drop on, it just forms little tin ***** that roll right off. Takes quite a while to heat each pin, so get comfortable. I ended up just doing every pin that was associated with a connector to the outside:

 

Now, you got to clean off the cover. First I tried a razor blade, but to no avail, so I got a scotchbrite pad and buffed it:





Also, shows just how thick that RTV is and how deep you have to cut to get the cover off. You have to clean the plastic off on the module as well. See all the pink circles on the inside of the cover? Those are thermal transfer paste. I put a fresh dab on there from my computer building hobby before putting the cover back on. Then, I found a use for my stock damper:



Let it sit for 24 hours, and reinstalled into the truck:



Yeah, I know my washer fluid is low, I was more concerned about getting the brake lights...

Anyway, has now been a whole day with no warning lamps