How to install an indicator relay switch on a motorbike

Motorbike indicators use a relay to flash the signals on a constant basis. Although these relays are quite durable, they do wear out over time. One sign is a constantly illuminated indicator. Replacing and installing a new indicator relay is one of the easier electrical tasks that a motorbiker may have to undertake, but it does require some familiarity with a motorbike's electrical system.

Replacing stock relays

Locate the bike'sindicator relay. Most motorbikes mount the relay near its battery or electronic control module, located under the seat or behind a frame-mounted side cover. Older machines may use a round, two-pronged relay, while newer machines are often equipped with a rectangular, three-pronged relay.

Disconnect the indicator relay from the motorcycle's wiring harness, pulling the wiring connectors off of the relay's prongs or unplugging it from the motorcycle's electronic control module. Install a new indicator relay into the wiring harness or electronic control module.

Turn the bike's ignition switch to the "ON" position and test the indicators for proper operation. If the indicators do not operate properly or only one side illuminates, check that the relay is properly installed and that the bulbs are in working condition. Turn the ignition switch to the "OFF" position.

Custom applications

Select a suitable location to install the indicator relay on your motorbike. Ideally, this area should be easily accessible and within reach of your motorbike's battery and electrical wiring harness. Install the relay using cable ties or a bracket.

Identify the indicator relay's prongs. The first prong on the right side of the relay is typically used to connect to the bike's main power line from the battery. The second prong at the top centre of the relay connects to the indicator switch on the handle bar, while the remaining prong on the left connects to the bike's ground wire.

Connect the appropriate wiring to the connectors using weatherproof electrical spade connectors. Turn the motorbike's ignition switch to the "ON" position and test the indicators for proper operation. Check that the turn signal relay is connected properly and that all indicator bulbs are in working condition if the indicators do not work properly. Turn the ignition switch to the "OFF" position.


An electronic indicator relay with a minimum amperage of 0.1A is required if you plan on using LED indicators on your motorcycle.

Things You'll Need

  • Indicator relay
  • Cable ties or bracket
  • Weather-proof electrical spade connectors
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About the Author

An avid motorcyclist, Chris Gilliland has immersed himself into the two-wheeled world while balancing work life and raising three daughters. When he is not managing the parts department of a local, multi-line motorcycle dealership, Gilliland can often be found riding, writing or working on his motorcycle blog, Wingman's Garage.