Looking at the circuit of the rumba, EXP3 pins 5 & 6 are pwm outputs.
I think EXP3 pins 7 & 8 are what you need to connect the signals to as these are ADC 9 & 10 inputs.
I think EXP3 pins 7 & 8 are what you need to connect the signals to as these are ADC 9 & 10 inputs.