All 650Fs No dash illumination

[RC74daniel]

Hey! I'm new here and just bought my first motorcycle, a 2016 CBR 650 F.

Unfortunately, the backlight of the dash is not working. (Did not just happen now, it has been the case since I bought it)
The numbers are displayed just fine and it shows the correct speed and rpm.
Additionally, the lights for the indicators and other control lamps work as usual.

The MIL shows the 86-1 code:

86-1 Serial communication malfunction
• Loose or poor contact of the related connector
• Faulty combination meter or its circuit malfunction
• Faulty ECM

I already followed the shop manual a little and checked the fuses for ODO/TURN and METER TAIL LICENSE PO. They both look healthy.
The bike just received a new, fully charged battery.
I also checked the brightness setting in the menu but that's not it either.

I'm hopeful it's just a bad contact but before taking the whole front apart to reach the dash, I wanted to ask whether you have some ideas.


Thank you in advance! Any help is highly appreciated.

 

[nateworks]

Have the same issue, dash brightness at full but doesnt illuminate. Please let me know if you find any solutions.

 

[RC74daniel]

Hey, quick update from me:
Took apart the whole bike today to reach the tachometer. The meter is in pristine condition, same goes for its connector. I disassembled the meter itself but the circuit board looks really good. Unfortunately, I don't think you can actually look at the LEDs for the backlight because the pins are glued to the circuit board? You can see the LEDs for the other control lamps, though. But maybe I'm wrong here. I doubt the issue lies there. I think the issue has to be further on the way to the ECU.
I will keep you posted!

 

[nateworks]

Hey, quick update from me:
Took apart the whole bike today to reach the tachometer. The meter is in pristine condition, same goes for its connector. I disassembled the meter itself but the circuit board looks really good. Unfortunately, I don't think you can actually look at the LEDs for the backlight because the pins are glued to the circuit board? You can see the LEDs for the other control lamps, though. But maybe I'm wrong here. I doubt the issue lies there. I think the issue has to be further on the way to the ECU.
I will keep you posted!

ended up being a fuse blown lmao. such a simple solution that i just overlooked.

 

[RC74daniel]

I already checked my fuses but I'll check again. I'm stoked it works for you now!
Which fuse was the issue for you? ODO/TURN or METER TAIL LICENSE PO? Or something else entirely?

 

[RC74daniel]

Hey Nate, the fuses weren't the issue for me, unfortunately. Checked all of them and even replaced the ODO/TURN and METER TAIL LICENSE PO ones although they looked fine. From your other threads I understand your indicator lights on the dash didn't work either, is that correct?

 

[RC74daniel]

Hey, thanks for trying to help but that just seems like a text from ChatGPT. As I mentioned, I already replaced the fuses, checked the dimmer switch, reassembled the combination meter for the switch malfunction (and I can cycle through the menu normally so that's not it) and replaced the battery with a new, fully charged one. Thank you nonetheless!
Does anyone know which of the pins could be responsible for the backlight? Here's the graphic:


I suspect BATT but I'm not sure at all. It doesn't seem like there's any pin which sole purpose is the backlight.

 

[Brammers]

The back light is probably an internally controlled function and as long as the dash is getting power should work.

I need to refresh my memory on the wiring diagram though!

J

 

[FogDucker]

This may help then. Looking for more material

 

[RC74daniel]

This may help then. Looking for more material

Thank you, I actually missed the inspection for the power input line and ground line. Though I think if there was anything wrong with them that the whole dash wouldn't be working. I don't think serial communication has anything do to with it because the dash works fine otherwise. But what's your take?

The back light is probably an internally controlled function and as long as the dash is getting power should work.

I need to refresh my memory on the wiring diagram though!

J

The dash is getting power. At least everything but the backlight works. Thank you for answering, love your bike and I really appreciate the work you put into it.

 

[FogDucker]

Thank you, I actually missed the inspection for the power input line and ground line. Though I think if there was anything wrong with them that the whole dash wouldn't be working. I don't think serial communication has anything do to with it because the dash works fine otherwise. But what's your take?

The dash is getting power. At least everything but the backlight works. Thank you for answering, love your bike and I really appreciate the work you put into it.

a short in a system can behave weirdly/randomly. Check the ground line first but to be honest dont waste your time on it. I know the drill about fixing it but sometimes replacing electronic parts makes much more sense than fixing them, unless you are technically inclined or there is something wrong with the bike's wiring and not the part

https://www.ebay.com/itm/1562319368...bvx+KhAFM/DwehNKIH6W2Lqh0=|tkp:Bk9SR7b5n7iQZA

 

[RC74daniel]

Using some paper clips and a multimeter I measured 12.3V between the GND and IGN pin. I'm guessing that means the dash is getting power? As there is no dedicated pin for the backlight, I'm guessing it's power is supplied by the general power supply of the speedometer. I think you're right and the issue is on the pcb. I have a friend who has some experience with fixing PCBs. I'll update as soon as I know more. Thank you again!

Besides, does anyone know what the BATT pin does? I researched a lot but couldn't find an answer.

 

[Brammers]

Looking at the wiring diagram, it almost looks like a power line (as it comes from the fuse in box 2) and feed only the dash, the optional connector and turn signal relay.

J

 

[RC74daniel]

Looking at the wiring diagram, it almost looks like a power line (as it comes from the fuse in box 2) and feed only the dash, the optional connector and turn signal relay.

J

You're right! I didn't think of looking into the HISS diagram. Then, the BATT pin which is connected to the Red/White cable seems to be the power line. So I should get a reading between BATT and GND.
Thank you loads, I'm very happy you are trying to help me! 🥰

 

[RC74daniel]

Well, it's even more confusing now.
So, the HISS indicator lamp in the combination meter has 3 lines: power (R/W), serial (W) and ground (G/R).
All of these lines are going into the 16P connector of the combination meter.
IGN seems to be one power line for the tachometer and BATT should be another one. Between IGN and GND I got 13V. I also checked for continuity between IGN and the positive terminal of the battery, which was successful. Between BATT and GND I got 23mV. So it's dead. I also didn't get any continuity between BATT and the battery positive.
So if the R/W cable is dead (which it clearly is), the HISS indicator lamp should not be able to light up. But it does.

Also, I dug around a little more in this forum. It seems the clock and HISS lamp of the tachometer is supposed be on even after removing the key from the ignition. This is not the case for me.
CBR650F Clock display always on

 

[RC74daniel]

Did some further investigation and the shop manual even calls the R/W cable "combination meter backup voltage".
I looked into the path of the R/W wire and it seems it also powers the turn signal relay. I measured 13V there on the R/W cable, so the cable is perfectly fine between the branch for the turn signal relay and the fuse box. Therefore, the open circuit is between the black 12P connector and the branch for the turn signal relay:


I will try to depin the 16P connector of the combination meter and connect a cable directly from the positive terminal of the battery to the BATT pin. If that works, I'll just need to put in a new cable.

 

[RC74daniel]

Found the open circuit, put in a new cable and reisolated the harness. The backlight works again and so does the clock and the HISS LED with the ignition off. Thank you for your help!



PS: Even with depinning tools, I could not get the pins separated from the connector. I'm no professional so maybe that's just me. Here's an image of the exposed connector:

 

[FogDucker]

Found the open circuit, put in a new cable and reisolated the harness. The backlight works again and so does the clock and the HISS LED with the ignition off. Thank you for your help!

View attachment 15223View attachment 15224

PS: Even with depinning tools, I could not get the pins separated from the connector. I'm no professional so maybe that's just me. Here's an image of the exposed connector:

View attachment 15225

you the man!