Motor shield motors not working?

Question

Arduino

I would be grateful if you could help a newbie understand.
Tamiya Twin-Motor Gearbox motors refuse to work. When power is applied directly to them, they work. But when connecting the motors through the motor shield and filling in the test sketch, nothing happens (does not work either powered by a PC or via batteries). The compiler does not swear, the arduinin itself is working, the shield too (the power light is on when the source is connected) I
use 4 AA batteries as a power source.
I used this code as a test sketch:
#include
AF_DCMotor motor(4);
void setup() {
Serial.begin(9600); // set up Serial library at 9600 bps
Serial.println("Motor test!");
// turn on motor
motor.setSpeed(200);
motor run(RELEASE);
}
void loop() {
uint8_t i;
Serial print("tick");
motor run(FORWARD);
for (i=0; i<255; i++) {
motor.setSpeed(i);
delay(10);
}
for (i=255; i!=0; i--) {
motor.setSpeed(i);
delay(10);
}
Serial.print("current");
motor run(BACKWARD);
for (i=0; i<255; i++) {
motor.setSpeed(i);
delay(10);
}
for (i=255; i!=0; i--) {
motor.setSpeed(i);
delay(10);
}
Serial.print("tech");
motor run(RELEASE);
delay(1000);
}
motors connected to port 4

Answer 1

If they work with direct power, then this is still a problem with the shield.
The presence of a power indication does not mean that the shield is working/correctly programmed.
What is a motor control shield?
Try like this :)

Answer 2

This one