98 Grand Cherokee ABS stays on help

[squrll]

I am getting ready to do a RC 4" lift on my sons 98 GC, he is in the Army training and this is going to be a surprise for him I am going over the whole jeep doing little maintence items before I start the lift next week
I have noticed that the ABS light stays on and my wife had a mech friend run the codes and it comes up with something in the ign. wire harness we have replaced the Ign switch but light still stays on, does anyone or has anyone had a problems like this? Looking at the master cly, there are only two wire come from ABS there Blk and grey ,is the ABS only to the front brakes on this jeep someone shoot me in the right direction please
thanks Squrll