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How To Test Motorcycle Turn Signals

This video covers how to test motorcycle turn signals, very similar to what we did last week with testing a motorcycle headlight. Sometimes you can fix your motorcycle turn signals with ease, but sometimes, they need to be replaced altogether. If your motorcycle turn signals are not flashing, this is a really quick way to determine if the problem is with your signals themselves, or with your wiring. This is also a great thing to do BEFORE you start installing motorcycle turn signals to make sure they aren’t dead on arrival, and it’s super easy to do!

How to power motorcycle turn signals directly from a motorcycle battery – all you need is:

  1. Motorcycle turn signals (duh)
  2. A motorcycle battery (if you have any motorcycle made in the last 30 years, you probably have one!)
  3. Some wire with some conductive properties (you might even be able to try speaker cable, but if not, click here)

How to test motorcycle turn signals – walk-through:

There isn’t a lot to give instructions on, but even though it’s a really easy process, there doesn’t seem to be any good resources on the internet that is specifically telling motorcyclists how to do this. So I’m gonna give the people what they need.

Basically, your mission is to attach one metal wire from each terminal of your battery, to the two cables coming from your motorcycle turn signals. In other words, you’re going to power your turn signals directly from your battery for testing.

Essentially the goal is to get the negative terminal of the motorcycle battery connected to the ground wire of your headlight. Here’s a picture I made for all of the visual people out there:

How To Test Motorcycle Turn Signals

Pretty easy, right? One wire from the negative battery terminal to the motorcycle turn signal ground (usually black) wire. One wire from the positive battery terminal to the turn signal’s other wire.

How to test motorcycle turn signals video

The picture was for the visual people, but for the really visual people, you can watch this how-to video.

Click the little unmute button in the bottom left corner to unmute the video.
Watch this video!

Notes / standard disclaimer

I'm a motorcyclist, not an electrician

1: Use the nut and bolt that came with your battery for a strong connection on your battery terminal.

2: This only works if your battery isn’t dead. If it is dead, put it on a charger. I used a Ctek battery charger because it has a motorcycle mode and a car mode (for more power).

3: Reminder: I’m not an electrician, I’m a motorcyclist. We’re just like electricians, except way more awesome, and we know little about electricity. Every electrical doohickey mentioned on this page might not be called by the right name. Deal with it.

Troubleshooting how to test motorcycle turn signals

This is a really easy way to check why your motorcycle turn signals aren’t flashing. You can follow the instructions above (check out the video) to easily see if the turn signals are faulty, or if you have a wiring issue you need to address. It’s a great way to troubleshoot your motorcycle’s turn signal wiring. For example:

  • Turn signals work when hooked up directly to the battery but not when hooked up to your motorcycle? You’ve got a wiring harness issue.
  • Turn signals don’t work when hooked up to the battery or when hooked up to your motorcycle? Turn signals are no good.
  • Turn signals don’t work when hooked up to the battery, but work when hooked up to the motorcycle? You’re doing it wrong.

How did we even get here?

A few weeks ago I installed a new Daymaker style LED headlight on my Harley-Davidson V-Rod, and that kinda failed (see for yourself).

So then I went back and tested my motorcycle’s headlight (check out the video here) Testing the headlight was part of how I fixed the problem this week.

The part where I beg you for your comments

*Ahem* If you have any questions or comments, please leave them in the comments section below! Things you can comment about:

  • If this helped you learn how to test a motorcycle turn signals
  • If I used the wrong words/terminology or made a typo somewhere
  • If this didn’t help you and now you burned your house down
  • Etc.

Overall leaving a comment just helps me to know that I’m not just out here talking to myself, so feel free to say hi!

About Adrian from YouMotorcycle

I started riding motorcycles in 2007, founded YouMotorcycle in 2009, and was working in the motorcycle industry by 2011. I've worked for some of the biggest companies in motorcycling, before going full-time self-employed in the motorcycle business in 2019. I love sharing his knowledge and passion of motorcycling with other riders to help you as best I can.


  1. A Motorcyclist, not an Electrician…..Oh and something of a Trekkie, obviously!!! What you are doing is great but just remember,,, Ye cannae change the laws of physics, cap’n!

  2. You helped one desperate fella from Poland :D Thanks a lot!

  3. I have an OEM rear turn signal that the running light does not come on and the turn signal when engaged has suffers from hyper flash (to front and rear on that side). Ive checked fuses, bulbs, relay, and even gone as far as getting a new OEM turnsignal but it appears to have the same issue.

    • Sounds like you’ve got a cut wire, you’re going to have to check to see if that wire is in fact getting power as it should and if not, trace the cable throughout your harness to see if it isn’t cut somewhere.

  4. Just wanted to drop a comment to let you know you’re not talking to yourself. I am new to motorcycles and just started riding 3 months ago. I’m no gearhead by any means, but I am mechanically inclined and have a smidgen of a clue about electricity. My first bike is a 250cc United Motors Renegade. I want a bigger bike but want to know how to take care of it, which is slightly hindered by my living in a 1 BR apartment with very few tools. However, I am determined to learn and look forward to what you can teach. Thank you for doing what you’re doing!

  5. What does it mean if the lights come on but do not blink? My right turn signals are not blinking but my left turn signals blink, could that be the relay itself?

  6. Spitball revolution. Problems become finite if you give it time. I’m dealing with a problem that I can’t expect anyone to know how to answer. I appreciate the fundamentals you guys are offering and I learn a lot, but what’s happening to me and my 2003 Honda CB750 Nighthawk (A) has gotten down-right personal and terribly under my skin. It’s almost metaphysical. It’s a life lesson, almost. Nothing I’ve had wrong has been beyond my scope of understanding and repairing since I took ownership of this bike 11 years ago. But now it’s a dyed-in-the-wool boondoggle.

  7. Just scooped up my first bike, but the turn signals aren’t playing ball, and I was convinced it was the signals themselves. It didn’t even occur to me to try this! Definitely giving it a shot to see if it solves my problem now.

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