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Question Current leak in clock/turn circuit

Eim

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Hi all,

I've got a current leak of 6.55 mA measured at the battery. Already found out there's only 0.03 mA draw left after unplugging the clock/turn fuse. The service manual says a maximum of 1.2 mA is permitted.
IMG_20231129_110126_edit_664335545851753.jpg
IMG_20231129_125629.jpg
IMG_20231129_110509.jpg

This circuit is responsible for the clock (in the dashboard) and the turn signals / hazard lights.

Using this nc700/nc750 service manual I've performed the following three diagnostic tests. And found out that by disconnecting the dashboard cable the current draw drops to 0.03 to 0.04 mA.
Honda nc750x ground line.png
Honda nc750x service manual power ground line inspection.png
Honda nc750x back-up voltage line.png

All three tests passed. However, at the back-up voltage line test something unexpected happend: the left signal lights turned on. When enabling the hazard lights also the other side lights turns on. In both lights are solid, not blinking. The service manual doesn't mention these lights may come on.
Update: found out these lights were on due to the 12V line making inadvertently contact inside the 16 pin connector.

IMG_20231130_171630.jpgIMG_20231130_175830.jpg
I noticed meanwhile the battery Voltage was dropping rapidly with all four indicator lights on. When I started the diagnosis it was at 12.8 V and by the end it was at 10.8 V.

Any clue what this could be and how to further diagnose and fix this issue?
This issue causes the battery to drain out over time.
 
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Of course, it never hurts to check the ground connection. But in your case, when the current leakage exceeds the permissible values, it can be assumed that the connection to ground is good. The deterioration of conductivity to ground causes an increase in resistance in the circuit, which results in a decrease of the supply voltage and current in this circuit.
If you stated that "by disconnecting the dashboard cable the current draw drops to 0.03 to 0.04 mA" (by which I understood that you disconnected the 16P connector to the combination meter), then you actually found what the problem is. Either there is a current leak between the connectors (requires cleaning) or there is an internal failure in the combination meter (not repairable).
 
Yes indeed lootzyan, disconnecting the 16P connector to the combination meter leads to a current draw of 0.03 to 0.04 mA. I have sprayed the 16P connector with silicon spray, as this is the only spray available. Anything else you'd recommend to clean the connectors?

I noticed something else. The current draw seems to be occuring when the dashboard shows the clock. I will try to explain:
-With the 16P connector connected, before turning the ignition key ON, there is no clock shown in dash: 0.09 mA to 0.11 mA.
-After putting the ignition key ON and back to OFF: 6.55 mA current draw, dashboard shows clock.

It seems that the leak isn't between the connectors but in the combination meter. I was wondering: is it possible to disable the clock? Anyone else that can share their current leakage with the clock shown for comparison?
I'll monitor if the clock turn will off after a period of time, say 24h (same as the HISS light), then re-check the current draw.

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Update ~22h later: the clock disappeared from the dashboard and the current draw went back to 0.11 mA (which is within service manual maximum).

Thus my conclusion so far is that:
1. There wasn't an issue to begin with. Still strange to see that the bike won't start after about a week of standstill. I have a new battery and will do more tests.
2. The Honda service manual is incomplete as it mentions 1.2 mA maximum for current leakage. There should be a remark that is after 24h with the dashboard clock OFF. OR it could be that my dashboard that is faulty. I'm asking somebody else here to check the current leakage with the clock on.
Scherm­afbeelding 2023-12-11 om 13.55.30.png
 
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