Lavens

I bought a 2000 S-10 two weeks ago and about a week ago my ABS and Parking brake light on the dash will come on and stay on after i start the truck. Most of the time if i turn it off and restart the truck the lights will go off. I read about changing the ignition harness that goes from the switch to the floor board of the truck and I changed this harness. Everything good for three days then I had the transmission flushed and they had to remove the battery to get to the hoses and now the lights are back. If Ilet the ABS and Parking light stay on. After about thirty minutes I will lose overdrive. But if I pull over and restart the truck and the Abs and parking light go out I will have overdrive again. Please help me.
2.2 4 cylnder
2wd
110,000 miles