On my 1999 Savana GMC 2500: While on jacks, my rear wheels did no stop when I applied the brake. Chevy told me my ABS needed to be replaced. I went to the Junk yard, got a $100 module and installed it. My first problem now, is that I had marked my lines, but the markings go covered in grease and I couldn't read them. I'm 90% sure I put them back in the right places. Is there a way to check this? After installing the ABS module, bleeding the brakes, the problem is exactly the same: I can't stop the rear wheels from turning at idle. I don't see a proportional valve. Is that done in the ABS?