actually for this truck code 10 and 20 refer to the right and left motor armature having a fault such as being shorted. Code 10 being right armature and Code 20 being Left.

you say you found some faulty/damaged sensor wires at the motors? This would be the harness that goes to the sensor inputs on the motors? it splits between both motors, 4 wires going to each motor? correct? They do have the terminals on in such a way you cant connect them completely wrong, but since polarity plays a part in this you still could have them connected backwards.

are you sure you hooked them up correctly?
On the motor sensor harness's there are wire numbers and colored wires that connect together:

On the left motor harness the wire number/color configuration is:
129 - Green wire
130 - Yellow wire
131 - violet wire
132 - orange wire

On the right motor harness the wire number/color configuration is:
124 - Green
125 - Yellow
126 - Violet
127 - Orange

Each harness should be tied together with each group of wires just long enough to reach thier respective motor.

Double check your connection configuration and make sure these wires are connected correctly.
Now there are other things that can trigger these codes such as bad transistors or maybe a bad drive board but lets check the simple things first.