this circuit does not work .. because if I change the polarization of the entry .. the LED does not light! so it is lit in this way .. the reverse he is off!
That way will work. The diodes are set up like a bridge rectifier so it doesn't matter which way the current is flowing, the diodes will correct it to run the LED. If the LED isn't lit then it is probably a construction fault.
Edit: What voltage is your motor? If it's really low then that will stop the LED coming on.
Here's a deluxe version
The LED now tells you that:
+12 supply is present
+5 supply present
Motor is on and drawing at least 1 amp
(adjust Rsense and R2/R3 ratio for specific current)
the diode network makes sure the current goes from A-K. it doesn't make sense just because you switched the polarity, since the diode network is a rectifier by configuration. must be something else which is the problem.