Background to why a diode kit is necessaryIn order to simplify the wiring systems on many motorcycles (otherwise known as cost saving!), many manufacturers opt to install a simple dashboard indicator signal warning lamp which flashes when either the left or right turn signals are activated.
The simple circuit used to add the warning lamp effectively bridges the left and right indicator circuits. When the left indicator is on, the dashboard warning light is powered by the left indicator circuit as you’d expect, but it uses the right indicator circuit as its ground path. The same happens in reverse when the right indicators are turned on.
What this means is that a small amount of current will flow through the dashboard tell-tale light, into the opposite indicator circuit (the one that should be off) and hence through the front and rear indicator bulbs on that side. When conventional filament bulbs are installed this is not a problem since the current is small and filament bulbs require much more current before they light up.
A problem arises however when we upgrade a motorcycles indicator lights to use LEDs instead of the conventional bulbs. LEDs are much more efficient and use significantly less power which means that they turn on with only a small input current. So the small current flow through to the opposite indicators via the tell-tale light is sometimes enough to make the other indicators flash too. This results in all four indicators flashing (rather like having hazard warning lights fitted) when either direction indicators are turned on. Clearly that’s not very useful.
The simple solution
The simple solution is to remove the bulb from the dashboard indicator warning light. This isolates the left and right indicator circuits and so prevents the cross-talk between the two sides. As a temporary measure, this is a useful solution if only to diagnose and confirm the cause of the strange indicator behaviour when you have installed LED lights. As soon as the warning light bulb is removed the problem should disappear and normal indicator operation resume.
This isn’t a good long-term solution though as you to lose the reminder that you have left your turn signals on. It is also likely that your bike may fail its next MOT test if the tell-tale light is not working correctly. Hence a more permanent solution is required.
The proper solution using diodes
The best long term solution is to slightly rewire the dashboard indicator tell-tale light by using diodes to isolate the left ad right indicator circuits. (Diodes are small electrical components which only allow current to flow in one direction, a bit like a one way valve in plumbing).
There are two stages to the modification. The first part installs two diodes to isolate the left and right indicator power circuits, and the second part provides an alternative ground connection to the warning lamp.
Everything you need to complete this modification is included in the MatchlessClueless LED indicator diode kit and the following instructions will guide you through the installation.
This modification works the same irrespective of what type of LED indicator lights you have fitted, although obviously the MatchlessClueless LED indicator boards work the best. The modification will continue to work even if you later swap back to traditional filament bulbs, so there should be no reason to ever need to undo your handy-work.
Please have a good read through all of these instructions before you start.
Installation guide contents (click to jump to a particular section):
The tools you will needThe diode kit includes Scotchlok quick fit connectors which remove the need for any soldering; you don’t even need to strip the ends of the wires!
Therefore the only tools required to install the diode kit are a pair of wire cutters and some pliers to close the Scotchlok connectors.
What’s included in the kitThe various components included with the LED indicator diode kit are as follows:
- 1x Diode assembly and wires
- 1x Scotchlok solder-free splice connector
- 3x Scotchlok solder-free pigtail connectors
This is everything you will require to make the modifications to your bike’s wiring loom to correct the feed-back flashing issue.
Step 1 – Preparing to install
Installation of the diode modification requires access to the wires that come from the various warning lights on your motorcycles dashboard. Depending upon the make and model of your bike access may be more or less difficult. If your biek has a fairing or enclosed bodywork around the headlight then you might need to remove some or all of this first.
As with any electrical work it is safest to disconnect the battery before starting work to avoid causing any accidental short circuits. At the very least you should ensure that the ignition switch, lights and indicators are all turned off.
Step 2 – Making the cut
At the back of your motorbike’s dashboard, locate the two wires which are connected to the indicator warning light. Most of the warning lights will have a power supply and ground connection, but the indicator lamp is slightly different. Each of the two wires is both the supply and ground – they switch round depending upon whether the left or right indicators is turned on.
Cut these two wires using a pair of sharp wire cutters (there is no need to bare the ends). It is better to cut the wires nearer to the multi-way connector rather than close to the dashboard unit. One of the cut wires will be used to make a new ground connection (see the next step below), so give some careful consideration to where best to make the cut before actually cutting the wires. “Measure twice, cut once!” as the saying goes!
Step 3 – Making a new ground connection
One of the two wires coming from the dashboard warning lamp that you have just cut will be used to make a new ground connection for the bulb (the other will be connected to the diode wire in the next step). If you are using a standard filament bulb in the warning lamp then it doesn’t matter which you chose as bulbs are not polarity sensitive.
However if you have already replaced the warning bulb with a LED equivalent (or think you might do so in the future) then it is important to chose the correct wire as the ground. Unlike conventional bulbs, most LED units are polarity sensitive (the MatchlessClueless LED boards are some of the few to include special circuitry to make them operate the same with either polarity). If you can trace the wires through to the warning light bulb holder, the one that goes to the outside of the bulb (i.e. not to the pin on the bottom) should be used as the earth.
For modern Triumph Bonneville, SE, T100, Scrambler and Thruxton models please see the section below which describes the typical factory wiring colours to make this process even easier.
The easiest place to make a connection to a new ground from is the ground lead from one of the other dashboard warning lights. The main beam warning light is the most common connection to use. You could run a new ground cable to a suitable earth point on the frame or even all the way back to the negative battery terminal, but this is far more complicated and much less neat than tapping into one of the adjacent warning light’s ground wires.
A Scotchlok splice connector is provided for making this connection. There is no need to cut the ground wire that you are going to tap into as the Scotchlok connector automatically makes the electrical connection when it is closed around the wire. Slot the connector over the wire so that it runs through the block under the metal blade (but don’t close this down yet).
Then take the cut wire from the indicator warning light that is to become the new ground connection and insert it into the right side of the connector (looking from the open side) parallel to the other wire. Ensure that it is pushed firmly against the stop inside the connector block so that it is under the metal gate when it closes.
When you are sure that both wires are correctly positioned under the metal gate in the connector, this can then be closed up using a pair of pliers. It is worthwhile gently pinching it up to start with and rechecking the wires are correctly positioned still, before then squeezing it full closed. The plastic flap can then be closed over the metal gate to complete the new ground connection.
Step 4 – Connecting the diodes
Examine the diode wire supplied in the kit and you will see that there are three wires coming out of it – two wires at one end and a single wire at the other. The diodes are provided with long (greater than 15cm or 6″) wires attached to give maximum flexibility with installation. In most cases these can be significantly shortened to make the installation as neat as possible, but the extra length is there just in case you need it.The single wire from the diode connects to the remaining cut wire from the dashboard indicator warning light. The double wires from the other side of the diodes go to the other sides of the two cut cables coming from the main wiring loom. It doesn’t matter which way round these two wires are connected as both are wired the same inside the diode wire package.
These three connections can be easily made by using the supplied Scotchlok quick connect pigtail connectors. Again there is no need for soldering, or even for stripping the ends of the wires. The ends of the two wires to be joined and inserted into the connector and then this is closed using a pair of pliers.
Full detailed instructions for using the 3M Scotchlok connectors can be found here.
Triumph specific instructions
The following instructions provide some more specific and detailed guidance to the colours or the various wires that you need to cut and tap into for the modern Triumph range of motorcycles, including the Bonneville, SE, T100, Thruxton and Scrambler models. The colour coding of the wires seem to be fairly consistent, although please note that they may vary between models and production years from those described below. Please use this as a useful guide, but be aware that your bike may be different and consult the appropriate wiring diagrams if you are unsure.
One of the two wires that come from the dashboard indicator tell-tale light is green with a white stripe (green/white). This is the wire which will become the new ground connection for the indicator warning light and which will be spliced into the ground connection from the adjacent main beam warning light.
The colour of the other indicator warning light wire may be plain green, or else green with a red stripe (green/red). Some people have also described it as being green with an orange stripe (green/orange), but the orange and red may actually be different interpretations of the same colour. Please note that there may be several green/red (or green/orange) wires coming from the back of the dashboard, so make sure you get the one that comes from the indicator tell-tale light. This second wire will be connected to the single wire coming from the diodes.
The ground wire of the main bean warning light is usually black. This is the easiest and most convenient wire to splice the new indicator warning light ground connection into.
Conclusions and your comments
So that’s the installation complete and your new LED indicators hopefully ready to give you many years of bright service. If you have any problems then please do not hesitate to get in touch via email or using the contact page. Please make sure your email address is correct so I can get back to you.
I would also be glad to hear how you found the installation process, any problems you encountered or anything that wasn’t clear or missing from this installation guide. Please let me know how I can improve the guide by leaving me a reply via the comment form below. Also if you have any photos you’ve taken of your bike during or after the installation process, then please email them to me so that I can add them to the customer’s photo gallery.
Finally, please let me know whether your Triumph bike had the same colour-coding of the wiring as I described above. If it differed, please post a comment below with the correct colour-code for your bike. It would also be useful if you could include the year and model of your Triumph. Many thanks.[disclaimer]
hi there would your kit fit a cbr 400 rr nc23 1988 as i have the same problem best regards gary
Hi Gary. I’m not sure of the exact wiring of your CBR400, but if you are experiencing the same problems described above when installing LED indicators, then this diode kit should do the trick! Cheers, James
james, this is all very systematic and having got the kit today (thanks) I’ll have a crack at it this weekend on my Enfield, but is there any chance of a sketch wiring diagram showing how the diode fits in? That would be v helpful to visualise what I’m supposed to be doing!
Hi Graham. Apologies for my delay in replying. There’s a nice diagram on the TriumphRAT website here which you may find useful:
Got it, thanks James.
hi James, just read your tips on led indicator troubles and wanted to say thanks. There was no way I was going to get diodes and wires inside my vs800 speedo so I simple put them in the wiring to the two rear indicators. But as I am in New Zealand and couldn’t wait for a diode kit I used two old 12v 5 w halogen bulbs, connected them to each indicator, encased them inside two large indicator lens and placed them under the seat. Magic! My indicators now light up like a Christmas tree!
My thanks again.
just fitted this kit to my 1997 Yamaha thunderace fantastic easy to fit and works a treat i just followed the very clear instructions provided on this page and can’t recommend it enough.
Thanks Sean, glad you found the install nice and easy! 🙂
Just come across this article & it appears to be very similar with an issue I’m having whilst attempting to wire an indicator warning LED into the circuit of a Suzuki project bike.
Is the kit still for sale or can you possible give me some information about the diodes you’re using
I shall be eternally grateful
Regards – Dave
Hi Dave. Yes, the diode wiring kit is for sale in our store area:
New stock will be available at the start of March. Regards, James
Smashing – will you update when available, or do I need to keep checking in?
Hi Dave. You can place a backorder now and I can ship the diode kit to you as soon as the new stock is ready, or else check back at the start of March and place your order then. Whichever is easiest for you! James 🙂
Hi, I have a monkey bike and am trying to connect a single led warning light for standard bulb indicators. Will this work for me?
Hi Lewis. I’m not sure of the exact setup you have on your monkey bike, but I think this kit should work for you. Connect the two wires coming out of one side of the diode kit to the left and right indicators respectively, and the single wire to your warning light. The other side of the warning light needs to be connected to the bike’s earth. This will give you a warning light that flashes when either the left or right turn signals are turned on, but maintaining the isolation between the two sides.
I have received your order and this will be on its way to you in today’s post.
Regards, James 🙂
I have an ’09 so this was needed. The harness wires are short so had to test position this to fit it in, but it all worked out. Tried no diode, but my ’09 needed it to get a normal blink rate. Connectors works fine, my first encounter with them. Can’t say enough about these kits, they are well made!
Thanks for the feedback Alex, glad your install went smoothly 🙂
I just need to know, what is the type of diode that is used i your kit. Because I’m from India and LED conversion kit isn’t available.
Hi Naveen. Our diode kits use low voltage drop diodes that are significantly over-rated in terms of current capacity and voltages compared to the typical loads in service.
The good news is that we can deliver to you India, just order from the product page here: https://matchlessclueless.com/store/led-indicators/led-indicator-diode
Been waiting a while to install diodes on my ’74 Honda CB360. Is this all I’d need to complete the fix? Just want to make sure its compatible.
Hi Chase. I’m not familiar with the wiring setup on your particular Honda, but if you are experiencing the same ‘cross talk’ problem described above making all 4 indicators flash together, then our diode kit is almost certainly what you need! The problem is common to most bikes that have one warning lamp which flashes whenever either the left or right indicators are on. Regards, James
Cross talk is definitely there. Just wasn’t sure how similarly they are wired. Here’s a link to my bike’s diagram, this make sense to you?
The wiring diagram is a bit fuzzy, but from what I can make out, there is a single indicator warning bulb that connects the left and ride sets of indicators. This is the standard wiring configuration and is what results in the cross talk between the sets of flashers, as you have found.
Our diode kit will correct this, but you will need to adapt the above instructions for your bike. The procedure is just the same, just that the wiring colours might differ.
I have installed the wiring kit but now I only get the warning light when the switch is indicating right and no warning light when its on the left hand side. All the indicators work fine. How can I solve this?
Hi Ben. My best guess is that one of the wire connections, the one to the left hand indicator side, has not quite made contact. Try gently tugging on the wire to seat it properly in the Scotchlok connector. Hope this help, James.
Hi, I have led indicators and stock bulb in dash, used to work fine but now is doing the hazard light thing, I pulled the dash bulb and Boom indicators started working properly. However my question is do i already have a diode wired in for it to have been working for some time and only now just started the hazard lights thing? And also the dash bulb when working properly used to be very dull, couldnt see through the plastic only when pulling out from das could i see that it used to work
Hi Brock. Sounds very strange that your setup all worked fine and then the hazard flashing thing started. I don’t think that your bike would have a diode already fitted, as if it did and this failed, it would result in the dash warning light not working, but not the hazard warning effect. I think installing a diode should solve your problem. Good luck! James
Hi, come across your website whilst searching for an answer to a problem on my 2012 Thruxton.
Ive fitted 4 x 3 watt cree chipset indicators to my bike & a squaredeals duel indicator relay. (This regulates the flash rate whatever indicators you use). All work fine except that the idiot light on the rev counter stays constant when using the indicators & does not flash at all. All seems to be working ok apart from that. Ive checked the wiring & even tried another relay, but to no avail.
Do you think your diode kit may fix this problem?, if not, any ideas where Ive gone wrong.
hi I have this kit and am having real problems on where to connect what wires to what on a 1996 Suzuki intruder vs600, help
Morning Will. Not sure what I can add to the above instructions really I’m afraid. I’m not familiar with your bike so I’m not sure what colours the wires are, but you will need to start by identifying the two wires that go to the dashboard indicator warning light. Do you have a wiring diagram for your bike? If you can send me that (send me a message via the contact page first) then I will take a look and see if I can tell you what colour wires to look out for. Kind regards, James
On my 2012 Bonneville I’m getting the same “crosstalk” flashing, BUT i’m not installing LEDs. Im installing smaller conventional bulbs. I also don’t have a Tach installed, so no indicator bulb is hooked up. Why would my signals be doing this? Would installing the diodes work for me, even if i don’t have a indicator light hooked up?
Hi Shawn. All seems a bit odd. If you don’t have a dashboard indicator warning light hooked up, then how are the left and right indicator pairs connected? If you have just removed / disconnected the warning light bulb, then the two sides should be completely separated (the dash light is normally the only connection between the two sides), hence I’m not sure how you are getting cross-talk between them. Is this some sort of custom setup you have? I don’t think the diode kit will work in the standard way, but the diodes might still help if installed another way. Can you provide a wiring diagram (a sketch will do) for what you have there? Regards, James
Bought your book some time ago, excellent read. I’m now in the middle of fixing an issue on my Ducati multistrada and wondered if you could tell me if a diode is directional (before I wore them in!)? I have bought two and it occurred to me that if they are like a one way valve then valves are directional. Can you tell I’m an ‘electrickery’ novice!!
There should be a mark on the diode to indicate the flow direction. Mine has a small arrow head on them
Thanks Dave, I’ll break out the magnifying glass
Bought this indicator kit to fix the issue descibed, the indicators now flash independently but the bulb warning light is not working. The issue is not the bulb as have checked and the other bulb warning lights work fine, can you think of a reason for this??
Never mind, have solved the problem, the Scotchlock connectors were not cutting through the wires properly and using plain block connectors instead did the job perfect
Hi Jack. Glad you solved the problem 🙂
There’s an installation guide for the Scotchlok connectors here which might have helped: https://matchlessclueless.com/product-info/installation-guides/3m-wiring-connector-installation/
One trick that I’ve found works well is to give the wires a gentle tug after closing the connector. This ensures that the metal prong inside cuts into the insulation and makes contact with the wire inside.
Kind regards, James
are you still making these kits?
Please advise. Thanks.
Hi. I have a 2002 aprilla rsv I have fitted led indicators and now have the magical 4way blinked flash when I turn the indicator switch in either direction what is the cost of the kit thanks andy
Hi Andy. Sorry, but our diode wiring kits are out of stock at the moment and I’m not going to have chance to make any more for the foreseeable future.
I did not have a solid black wire coming from the instrument display for the main beam. There was a black with white stripe – tried using that and the indicators now flash independently, but the headlight has become extremely bright (and hot), and the alarm is no longer working correctly from the fob. Nike is a 2005 triumph Bonneville t100.