Since when have direction indicators actually been flashing?

Bosch presented the first illuminated direction indicator in 1925. This was a fold-out arm on the side of the vehicle, with a permanent light for better visibility. They had one small disadvantage: in severe cold, the fold-out mechanism tended to freeze, and that was the end of what was actually good functionality. In the late 1930s, the first fixed (directional) indicator lights appeared in the United States (without mechanics), which drew attention to themselves with a certain flashing frequency. At Harley-Davidson, turn signals were available on F and FL models starting in 1949, and by 1958 they were listed in the parts manuals for Sportster models.

Do I have to have turn signals on my bike?

In Germany, they were mandatory as of January 1, 1962, which means that if your first registration - of your Harley, of course - is before that date, you don't need directional indicators. You must use the hands. In Austria, this limit is later, namely 1983. In Switzerland, even later: 2013 is the cut-off date. But in both Alpine countries, if older motorcycles have turn signals in their original state, you can't remove them - no matter how old the Harley is.

Can I simply replace turn signals?

Sure! Not just as a replacement part, also if you don't like the OEM style or if it doesn't match your custom bike. In North America, the replacement parts must have an SAE or DOT marking, in the EU and many other countries they must be approved according to ECE (E-mark). However, these approvals only apply to visibility. Since the flashing frequency is also regulated, you have to take care of that, too. If the power consumption (the watts that are printed on the turn signal) changes the flashing frequency, you must provide a compensation. For this we have load independent flasher units or load equalizers.

My turn signals do not flash, they just light up? What is the problem?

Before you change the flasher unit, just check the power consumption of the flasher. Do you have LED turn signals installed? This is probably the reason. The power consumption of these lighting wonders is usually so low that the flasher units operate at such a high frequency that the result is a continuous light. Then the power consumption must be corrected with a suitable flasher unit or a load equalizer.

The bulb in my flasher keeps burning out. What can this be?

The problem occurs mainly in older vehicles when the bulbs do not have a proper ground. The vibrations then cause voltage spikes in the bulbs that cause the filaments to burn out. Anyone who has ever accidentally installed 6 V bulbs in a 12 V bike knows what is meant.