If the starter does not turn, then first of all, you should check whether there is the desired voltage of 8 V at terminal 50 of the solenoid valve. If the voltage is less than the specified level, you will need to check the wires in the starter circuit using the electrical circuit. Whether the starter will retract at full battery voltage can be checked as follows:
Do not engage low gears, turn on the ignition.
thick wire (cross section not less than 4 sq. mm) connect clamps (30) And (50) starter. If the starter engages correctly, the defect is in the starter wire. If the starter does not engage, it will need to be removed and inspected.
Test conditions: wire connections must be securely fastened and not oxidized.