It sounds like a high resistance path where you are getting a voltage drop.
All electric motors have a startup surge because when they are stationary they are a dead short electrically, it's only as they start moving that electrical energy is absorbed and changed into movement/kinetic energy. So the first burst of current can be between 3 to 8 times the running current.
So what does this mean for the wiring?
Well that motor still needs that fixed amount of energy to start, so it will always try and draw it.
Remember that for electrical energy power(watts) is current(amps) times voltage(volts)
So if you have voltage drop due to thinner than required cable, or cable with poor connections that adds resistance, then the only way a motor can get more energy from a falling voltage is drawn more current.
Now if left unchecked a jammed/stalled motor could continue trying to draw more current, generally with a battery/alternator/generator that will cause the voltage to drop further and more current drawn, a vicious cycle where the current will climb very high and start melting things - that's why all motor circuits are fused (and now you know why they are higher than you might expect) but also motor controllers generally measure the current drawn and if it's unusually high or the surge lasts too long power will be cut.
This is exactly the what the door module is doing and why you get that message.
There are two physical reasons why the motor can be drawing too much current and from a controller point of view they look the same:
- There is more resistance/drag requiring more torque for the motor to start
- There is more voltage drop in the electrical supply than designed for