The yellow wire and the resistor will NOT stop the step from functioning. The yellow wire is just a 12 volt Ignition power to tell the steps to retract when the entry door is closed and the Ignition turned ON. The Resistor is Winne built and installed and usually is there because they are trying to prevent feedback from that Yellow wire to some other Motorhome appliance.
1. What do you mean you connect the Brown wire and the motor spins? All the brown wire is, is the feed from the Magnetic door switch
2. The White wire needs to have 12 volt power for the step to operate. Kwikee changed the inside ON/OFF switch that white wire comes from a few years ago. What they did was reverse the LOGO on that switch and reversed which side of the switch says ON or OFF. So, there should be 12 volt power to that wire when that inside switch is engaged.
3. The LARGE RED wire at that 4 wire will have 12 volt positive all the time
4. With the system connected back to original, the quickest way to determine what is going on is, With the white wire 12 volt positive and the RED positive, the Brown should have Ground(negative when door is closed), when you open and close the door that amber light should come ON when door opened and OFF when door closed. That means the control module is probably GOOD
5. IF you removed the motor and it is not connected to the Transmission, odds are it will work. A BAD motor will usually work when removed for bench testing, because it has a dead spot in the armature and by removing you jarred the armature and without a load on it will then work. Doug