I found this random black wire that was just sitting on top of a bolt near the abs unit. Not sure what it is, looks like maybe a ground wire but not sure. Anyone know what it may be for? It seems to split from the harness just before the abs. See pics, hopefully you can see where it comes from.

DT,

We all seem to have that feller.  Not sure where it goes etc.  But it has been loose on almost everyones vehicle.  Some people put it to ground.

 

HTH
 

Hag

 Kinda thought it might have something to do with a brake controller or something. My suburban had a bundle of wires in about the same spot to wire in a trailer brake controller. It don't seem to be hurting anything so I'll leave it for now.

Does it have a in-line fuse?

Not that I could see.

On my '98 that ground wire is bolted to the ABS system. The truck is rear wheel ABS only tho...