If the frequency of the indicator signal of one side is higher than the frequency of the signal of the other side, this is a consequence of damage to the incandescent lamp or a break in the supply wire.
In many other cases, the reason for the failure of the direction indicator is the relay-breaker. The relay is removed to test. Contacts 1 and 2 of the relay are connected with auxiliary wires to the battery, see fig. G-5403. Then connect 2 incandescent lamps in parallel (21 W) between terminals 1 and 3. The lamps should flash at a rate of 60-120 cycles per minute. If only one lamp is connected, the cycle rate increases to 140 per minute. Otherwise, replace the relay-breaker.
If a new relay is not available, insert a thin wire between terminals 2 and 3 into the relay plug.
Attention: When doing this, you need to be careful with the sensitive contacts of the relay and do not damage them. Bend the ends of the wire before installation. Replace the defective relay.
Turn on the ignition. Now, after pressing the switch, the corresponding turn signal lights up, but does not flash. Turn on the direction indicator with the switch lever, reproducing the rhythm of the direction indicator. Replace the breaker relay with a new one as soon as possible.
If the direction indicator does not light up despite the jumper being installed, then the fault is in the breaker relay or in the supply wires.