Simple and Effective Mounting Guide for Motorcycle LED Turn Signals

How to change motorcycle turn signals to LEDs?

You want to replace the turn signals of your motorcycle, your Café racer, with handlebar end LED turn signals, mini LED turn signals, built-in turn signals, sequential, etc., but you don't know much about electrical circuits and don't really know where to start.

We offer this guide to help you step by step . This tutorial will allow you to quickly and easily learn the basics that will help you better understand the various steps required to install turn signals and LEDs.

Take the time to read this guide to familiarize yourself with the various components. You will then be able to equip yourself with the appropriate equipment and effectively mount LED turn signals on your motorcycle.

• Assembly diagram of motorcycle LED turn signals
• Operation of the turn signal unit
• How to adjust the flashing speed of the LEDs?
• How to connect motorcycle turn signals to 1 or more wires?
• Materials and parts needed
• Conclusion
• For further

Electricity is an area that, in general, worries. And it must be admitted that the electrical diagram of a motorcycle, where dozens of wires intersect, is not really made to reassure. This is why we are offering you a simplified presentation of the turn signal motorcycle electrical circuit. This will give you a more accessible and clear overview.

We suggest that you go through precisely, through 7 steps , the different phases detailing the operation of the turn signals and the necessary elements in the electrical circuit of a motorcycle:

1. Basic assembly : the front and rear indicators are here connected directly to the motorcycle's 12 V battery . At this time, no switch is integrated into the circuit, so all 4 are on, without being able to flash.

2. Switch to activate the turn signals : in order to trigger the left or right turn signals, a command must be added to the circuit. For example, the switch , used in the diagram below, activates the desired turn signals. Note that for the moment, if the left or right indicators are selectable, they remain fixed in the absence of a control unit.

3. Choose the right fuse for the indicator circuit: motorcycles are fitted with a general fuse (here 50 A) which protects the entire harness. Each circuit has its own fuse. Here, the 7.5 A fuse isolates the turn signal circuit from a possible short circuit. Unless there is a very large short, it will melt first, protecting the entire harness.

• conventional bulbs : taking 21 W bulbs as an example (i.e. 4 bulbs x 21 W = 84 W), powered by a 12 V battery, it will be necessary to install a fuse of at least 7 A (84/12) ;
• LED indicators : their consumption, much lower, will give us, for example, on 4 LED bulbs of 2 W a value of 1.15 A . (2x4=8W; 8/12). If in this case a 2 A fuse is sufficient, there is no need to change the one already in place if higher, such as a 7 A for example.

4. Role of the Neiman: until now, our indicators, connected directly to the battery, are static and constantly on. A French invention by Abram Neiman (1931), the Neiman was originally a lock attached to the steering column. The Neiman, or "starter contactor" activates the indicators when starting the motorcycle, but also when stationary, in the parking position.

5. Operation of the direction indicators in the Warning position: in the "off" position, the hazard warning lights button (warning) authorizes independent selection of the right and left direction indicators by their control. When “on”, it activates all four simultaneously regardless of the position of the stalk .

6. Connection to the counter indicators: whether through a simple display as shown in the diagram, or in a counter , their connection provides a visual indicator on your cockpit.

7. The turn signal unit: with the Neiman and the possibility of activating the 4 turn signals as a hazard warning light, these can be switched on and off at will, but still do not flash! Indeed, the essential part for the proper functioning of the indicators is missing: the control unit (or flashing relay) . A particularly useful invention which avoids the tedious task of alternating the flashing sequences yourself!

The control unit, now electronic , bimetallic on old motorcycles such as the Café racer, has the role of managing the flashing frequency defined by the Highway Code:

Article 24 : Order of July 16, 1954 relating to vehicle lighting and signaling ( Amended by Order of June 28, 1979, see init. ) "The direction change indicator devices must consist of flashing lights in a fixed position emitting an orange light forwards and backwards, not dazzling . The flashing frequency must be 90 flashes per minute with a tolerance of more or less 30 sec. »

Back to summary

The flasher unit (or flasher relay) is a small unit powered by the battery. Its role is to trigger the flashing of turn signals and hazard warning lights. Today, the control units are mostly electronic , the bimetallic models were fitted to old motorcycles.

In a bimetal system, the power plant is provided with two blades welded together, of different metals or alloys. Their own expansion coefficients cause them to bend under the effect of temperature variations.

Thus, when the electric current passes, the bimetallic strip heats up. One of its blades retracts , breaking contact . As it cools , it resumes its initial position, allowing current to flow again, and so on.

In the majority of cases, a control unit, or relay, manages all the indicators. If they are not wearing parts, they are nevertheless subject to possible malfunctions. Take care to check, before changing it, that the problem does not come from the turn signals themselves.

The price of a plant generally varies between 10 € and 20 €, some can however reach 40 €.

Back to summary

If your motorcycle was not originally equipped with LED indicators, you risk being confronted with excessively fast flashing speeds on an electronic control unit, or slow or fixed ignition on a bimetallic control unit.

With LEDs, power consumption is very low . They actually generate insufficient heat to heat the blade at the expected frequency. 3 solutions to normalize the blinking rhythm are possible:

1. Add resistors

To allow a control unit, not designed for the use of LED bulbs, to operate correctly, it is necessary to provide it with the amount of current it needs. Thus, the control unit of a motorcycle fitted with conventional bulbs will be suitable, for example, for 21 W bulbs and not 2 W.

To solve the flash speed problem, you will therefore need to add resistors in parallel with the LEDs. In this example, it will be essential to install a resistor of at least 19 W to reach the original 21 W.

Your indicators will then have the required flashing speed, but at the cost of higher power consumption and a greater impact on the battery, especially if you frequently use the warning position.

Note : the resistors heat up , so position them so as to isolate them from other electrical components. They need to be ventilated , so don't enclose them in a case or plastic.

2. Change the turn signal unit

As seen above, resistors have the major defect of readjusting power consumption and consequently losing the savings achieved by LED technology.

When mounting LED indicators on a motorcycle, the simplest thing is therefore to opt for a control unit that is perfectly suited to LEDs. It may happen that some relays have different connections. Indeed, depending on the models and brands, each motorcycle will have specificities to which it will be necessary to adapt.

3. Modify the parameters

On some models, such as the Triumph Street Twin , the direction indicators can be adjusted by modifying the parameters in the on-board computer .

On other motorcycles, such as the Ducati Scrambler , no action is necessary: ​​the on-board computer manages everything automatically.

Back to summary

Depending on the turn signal model, you may be faced with different mounting configurations depending on the number of wires, which can be confusing.

• How to connect 1-wire motorcycle turn signals? 1-wire indicators come from old motorcycles. The body of the turn signal acts as a ground, once attached to the chassis or handlebars. The only wire to connect is the power supply. When installing a 2-wire flasher in this case, the second wire will serve as a ground that can be found on the headlight which is never very far away.
• How to connect 2-wire motorcycle turn signals? Nothing special, the most common model: 2 wires "+" and "-".
• How to connect 3-wire motorcycle turn signals? 2 “+” wires and a mass. On some motorcycles there are 2 “+” wires for the turn signal and warning function. But we can very well use only two wires: a "+" and the ground.
• How to connect 4-wire motorcycle turn signals? For 3 in 1 indicators, with integrated headlight. 1 "+" for the indicator, 1 "+" for the brake light, 1 "+" for the position light and 1 ground.
• How to mount sequential LED indicators? The connection is similar to that of conventional indicators, "+" and "-". No modifications to be expected. they are self-managed.

Back to summary

In our online store you will find a wide selection of indicators, from €18.90: from classics to LEDs from the brands Motogadget, Highsider, Koso, Brazoline, Kellermann etc., indicators for Café racer, Chopper and for all motorcycle styles:

• vintage turn signals;
• indicators on mirrors;
• halogen indicators;
• LED indicators;
• mini turn signals;
• recessed indicators;
• sequential turn signals;
• etc

Do you need to complete your accessories and tools to mount your indicators? Visit our electrical and mechanical departments:

• relay or resistor;
• central;
• fuse;
• wire stripper;
• adhesive tape for cables;
• Phillips screwdriver ;
• connection kit on original wires (connect the indicators to the original cables of the brand of your motorcycle without having to strip them);
• etc

Back to summary

We hope that this little guide will help you see things more clearly and help you to mount the LED turn signals on your motorcycle. However, if you still have question marks, do not hesitate to use our contact form . We will respond as soon as possible.

If your motorcycle was not originally fitted with LEDs, it is preferable to opt for a turn signal unit designed to manage the LEDs, it will be simpler , more efficient and more economical to use. Like any work done on a vehicle, and a fortiori on a motorcycle, take your time and take care of your connections.

If you are replacing turn signals on a motorcycle under warranty, it is best to use original wire connection kits . You will not need to cut the cables and you will keep the warranty of your motorcycle.

Changing the turn signals can be an opportunity, especially on an old motorcycle , to renovate the entire wiring harness. On this subject, we invite you to read our article: “ How to Redo the Wiring Harness of your Café Racer? ". Here you will find detailed information and learn about the many advantages provided by the electronic control unit of the German manufacturer Motogadget Mo.Unit Blue , especially for the installation of turn signals .

Important : before starting to install your indicators, or any other electrical accessory, disconnect the black “-” cable from your battery first!

Back to summary

feedback