If on one side the blinking rhythm is faster than on the other, then on "rapid" board, one of the lamps is out of order or a wire is broken.
In all other cases, the reason lies in the breaker relay. To check, remove the relay and use the auxiliary wires to connect relay contacts 1 and 2 (pins next to each other) with battery. Then connect to pins 1 and 3 two incandescent lamps connected in parallel for direction indicators (21 W), the lamps should flash at a frequency of 60 to 120 times per minute. If only one lamp is connected, the frequency will increase to more than 140 times per minute. Otherwise, replace the breaker.
If a new relay is not available, insert a thin wire between pins 2 and 3 in the relay connector.
Caution: Do not damage sensitive relay contacts. Before inserting, bend the ends of the wire so that there are no sharp edges Insert the defective relay again. The relay legs are so long that the relay can also be inserted with a jumper.
Turn on the ignition. When the direction indicator switch is switched, the direction lamps of the corresponding side are now constantly on. By quickly turning the switch on and off, you can simulate the operation of a breaker. But at the first opportunity, the relay should be replaced.
If the direction indicators do not light up and with a jumper, the cause of the defect lies in the switch or in the wiring.