Solution
Unfortunately there's no resistance specified for the motor bridge of the module and the reason is that it's a non-linear/non-ohmic circuit. It's basically 4 transistors arranged in such a way that you can choose to output No Voltage, Positive Voltage, or Negative Voltage. The images below replace the transistors with switches, but it shows how the part works.
![](/servlet/rtaImage?eid=ka03q000000t9t0&feoid=00N0Z00000HEWRt&refid=0EM0Z000000qvnc)
Above: H Bridge in "off" configuration. Below: H Bridge with current flowing in both directions.
![File:H bridge operating.svg](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/H_bridge_operating.svg/800px-H_bridge_operating.svg.png)
Transistors don't have a resistance, per se, so there will be negligible voltage drop across the transistors in this H-bridge. They will basically act as conductors when in the "on" position.