MT07 2020, No working Auxiliary and Tail/Brake light

[HammerY]

This is a follow up to a previous post. I'll try to make this post as clear as possible. The auxiliary light and the Tail/Brake lights are no longer working because I made a mistake wiring an aftermarket signalling light with auxiliary light. The fuses are all fine after I checked them a couple of times. Turn signals work fine and the bike starts normally with no issue.

I checked the service manual for troubleshooting steps and it instructed me to check the Main switch as a next step if the fuses are fine. Here comes my issue, The Electrical component diagram shows what wires of the Main switch to check. the other photograph is what I ended up with when I followed the main switch cable lead and the wire colours don't match with a highlighted part in the electrical diagram.

The photo shows three couplers, a single wire coupler, three wires and five wires water-resistant coupler

Bear in mind that the service manual is for MT07 for US models and I know there are small differences in electrical design between US MT07 bikes and European and Asian MT07 but not sure if the difference applies to the main switch wiring diagram.

 

Any feedback is highly appreciated

Edited July 1, 2021 by HammerY

[ElGonzales]

Have you checked your Horn?

I have a slight idea it might also not work.


Edit:

 

Your main switch is working, otherwise nearly the whole bike would be electrically dead. Dash dead, turn indicators dead, headlight dead...
Check the wiring diagram. Tail/Brake light and Auxiliary Light are powered by the signaling system fuse. Check this fuse again by measuring it's electrical resistance. If you don't have a device to do this, just replace it by one of the spare fuses you find in the fuse box.

If then the tail light is still defective we can search for the lost voltage.

Edited July 1, 2021 by ElGonzales

[HammerY]

On 7/1/2021 at 7:36 PM, ElGonzales said:

Have you checked your Horn?

I have a slight idea it might also not work.


Edit:

 

Your main switch is working, otherwise nearly the whole bike would be electrically dead. Dash dead, turn indicators dead, headlight dead...
Check the wiring diagram. Tail/Brake light and Auxiliary Light are powered by the signaling system fuse. Check this fuse again by measuring it's electrical resistance. If you don't have a device to do this, just replace it by one of the spare fuses you find in the fuse box.

If then the tail light is still defective we can search for the lost voltage.

I haven't checked the Horn; If I'm going to do that, I need to reassemble the fuel tank bank again. I removed the fuel tank to be able to access the main switch coupler

The service manual guideline suggested checking the main switch after the fuse box, and as shown in the electric diagram, it shows what wires need to be checked.
The Auxiliary light is powered by a different fuse than the signalling light system. Auxiliary light is protected by a 2.0A fuse, while the signalling light system is protected by a 10.0A fuse.

I'm sharing the link to a copy of the service manual as It might help with how to make proper troubleshooting the problem

<

2018-2020 Yamaha MT-07 Service Manual.pdf - Google Drive

>

[ElGonzales]

The 2.0A Auxiliary fuse (#6 in wiring diagram) connects the DC Auxiliary outlet (#85) where you can plug in something like USB Chargers or other additional devices. This connector is located on the left side of the bike, close to the regulator/rectifier. On a brand new bike there is nothing connected to it. But it has nothing to do with the bulbs in the headlight (in factory configuration).

The 10A signaling system fuse (#8) connects the auxiliary light (#77) AND the Tail/Brake light assembly (#80) via the joint coupler (#24). Follow the blue/red wires.  As far as I understand, this are the things which are not working right now.

Additionally this 10A signaling system fuse also connects the horn (#59) via the horn switch (#71) and License Plate Light. Thats why I assume that they are without function too.


As a first step I would simply measure the voltage at the  incoming terminal of the 10A fuse #8. There has to be battery voltage (12.x V) while the ignition (main switch) is turned on. If this is the case, up  to this point in the electrical  path all the cables and the main switch are all right.

Edited July 2, 2021 by ElGonzales

[HammerY]

46 minutes ago, ElGonzales said:

The 2.0A Auxiliary fuse (#6 in wiring diagram) connects the DC Auxiliary outlet (#85) where you can plug in something like USB Chargers or other additional devices. This connector is located on the left side of the bike, close to the regulator/rectifier. On a brand new bike there is nothing connected to it. But it has nothing to do with the bulbs in the headlight (in factory configuration).

The 10A signaling system fuse (#8) connects the auxiliary light (#77) AND the Tail/Brake light assembly (#80) via the joint coupler (#24). Follow the blue/red wires.  As far as I understand, this are the things which are not working right now.

Additionally this 10A signaling system fuse also connects the horn (#59) via the horn switch (#71) and License Plate Light. Thats why I assume that they are without function too.


As a first step I would simply measure the voltage at the  incoming terminal of the 10A fuse #8. There has to be battery voltage (12.x V) while the ignition (main switch) is turned on. If this is the case, up  to this point in the electrical  path all the cables and the main switch are all right.

Thank you so much for the feedback. I’ll follow up with your advice and let you know of the outcome

Edited July 2, 2021 by HammerY

[Jerzee]

Check to see if you have voltage at the tail/brake light coupler (#2 Page 2-21), and make sure it is connected as well...

[ElGonzales]

I took some pictures of what you can expect. I only have my 2014 MT-07 for reference, but I think there are no differences to newer models in this area of wiring. 

The negative black measuring tip of the digital multimeter is clamped to the negative battery terminal. (A blank spot at the metal frame is also a possible spot for negative ground connection)
Instead of a gauge, a simple 12V bulb with cables attached would also work and glow.

1. with the ignition (or "main switch", as the Japanese manual calls it) turned on, 10A "signal" fuse removed, the upper terminal of the 10A signal system fuse delivers battery voltage. It is connected directly to the main switch.

With this result, we know that the main switch and the cable connection between main switch an fuse box are fine.

2. The bottom of the fuse box. I took a look out of curiosity
-the thick brown/blue wire comes from the main switch.
-the two blue/red wires are going to tail/break/aux. light etc.
Exactly like drawn in the coloured wiring diagram at the end of the service manual. That's nice.
 

3. Now we put the signal fuse back in to reconnect brown/blue with blue/red.
As expected, there's our battery voltage at the pin of the tail/brake light coupler. I touch the pin for tail light. Voltage is also switched to the brake light pin by pressing the brake.

Remove the signal fuse: Voltage is gone

Now we know the connection between the fuses lower terminal contact and the coupler is fine.
There is not much more regarding the electric supply of tail/brake light.

Edited July 3, 2021 by ElGonzales

[HammerY]

On 7/2/2021 at 11:27 PM, HammerY said:

Thank you so much for the feedback. I’ll follow up with your advice and let you know of the outcome

I solved the problem and it turns out i checked the wrong fuse. Thank’s a lot for your reply, its the reason I was able check the correct fuse and it was busted.

The reason I missed checking the correct fuse is because the turn signal lights are fine so i believed that it can’t be "signaling fuse"

[ElGonzales]

Glad you found it, it's always good to make really sure  the most likely and easy to access things are okay before one takes everything apart.

(I already knew it was the signal fuse two weeks ago, but my back was hurting badly and I forgot to answer the thread )

[andrewhtf]

On 7/5/2021 at 2:55 AM, HammerY said:

I solved the problem and it turns out i checked the wrong fuse. Thank’s a lot for your reply, its the reason I was able check the correct fuse and it was busted.

The reason I missed checking the correct fuse is because the turn signal lights are fine so i believed that it can’t be "signaling fuse"

The exact same problem with mine just now. I assumed signal fuse is fine since the signal is blinking. Thanks to your thread, it saved me a trip to the shops and realised how silly I had been

[Pursuvant]

@ElGonzales if I had an electrical problem you would be the man I would want advice from. That's a damn fine thing to do, to open up your bike and step thru the trouble shooting, taking pics and explaining what your doing for another forum member.

[OtterSpace]

Guyzzz same problem here. But my signal fuse blows up again after replacing. It all started after headlight replacement. Gonna check tomorrow with gauge...

 

 

[jasmine-v4]

Can some one Help about turn signals Not working on 2020 Yamaha MT-07 not even power at all at the Fuse wiring about Turn signals