I dont think anyone could help me out with this, but its worth a shot.
I parked in a level parking lot.. i put my 99 1500 silverado in reverse
and lightly pushed the brake to stop. i heard my ABS pump turn on so i
put it in park and released the brake.. the motor still was running.. i
turned the truck off and took the key out... it was still on... i
went out and bought a system scanner to see what codes i was
throwing... turns out my hook harness on the truck is shot!
anyone got any ideas with whats going on?

 

One or both of The ABS sensors on your front wheels has gone bad. It is telling it that it needs to be engaged, you need to replace the bad ABS sensor on the front wheel, in the mean time you can remove the fuse from the fuse panel under the hood of the truck marked for the ABS system to keep the battery on the truck from discharging down. the easiest way to find out which sensor is to use a Multi Meter and check the resistence on the sensor, According to Haynes manual it should read 850 - 1230 Ohms at 41 to 116 degrees Farenheit..... there is also a toothed ring inside the wheel bearing assembly if it becomes damaged then it will read a decrease in pulses from side to side and cause the same issue... repair is to replace entire wheel bearing assembly on the front wheel for the damaged side..... the third and last possibility is produced from the rear wheels speed which is interpreted from the VSS (vehicle speed sensor) it is located in the extension housing at the transmission on a 2WD and on the transfer case on 4x4 models. the VSS provides information to the PCM to indicate vehicle speed..... the ABS and VSS work together and signal back to the PCM to determine vehicle speed. this is what activates the ABS system.