[Birchy]

So my 2021 Cforce 600 Touring started getting a little hard to start as the motor wouldn't turn over so I replaced the battery, and it started a few times and didn't a few times, and then it wouldn't start at all, just clicked when depressing the start button.  When I turned the ignition lock switch the lights would flicker, and after trying to debug the issue the bike does nothing now, except for a few weird power things.

I saw a video about the starter relay & fuse module melting () so I checked that and the 30A fuse was pooched and the connector was slightly melted, so I replaced the 30A fuse. 

t=68s
Now it basically does nothing, I can't see, hear, do anything - no fuel pump sound, no horn, nothing.

Voltage at the Light/Control_Signal/DC_Outlet dropped very low when the ignition switch was turned on, so I pulled those 3 fuses and the 12.8V at the battery only dropped to 12.56 at the ignition key switched 12V side of the pulled fuses, which seems like is a big drop with no load.
When I inserted the Lights fuse or the Control_signal fuse the voltage at the fuse drops to a couple volts .
Note that when I connect up a battery the display toggles on and then off again, so it looks like the display is active.

From the schematic in the shop manual (I ordered one from CFmoto USA as CFmoto Canada doesn't sell them) the ignition key switches power to the three aforementioned fuses and the EPS module.
When I insert either the Lights fuse or the Control_signal fuse the voltage at the fuse drops to a couple volts, the voltage at the battery remains 12.8V  (the DC outlet fuse does nothing as there's no load on it).
I disconnected the EPS module and the Song Remains The Same (song quote for us old buggers).

Help please!
Thanks
  John

[NMKawierider]

Clearly there are other electrical issues. Might check the AUX relays and I guess any other connectors that may have gotten wet. One note- the key switch is known to fail often on these.

[Birchy]

Unfortunately it doesn't seem to be the easy fix of the key switch as I shorted it out and it still does the same thing.

The Vbat on the Light/Control_Signal/DC_Outlet fuses (from the key switch) drops to a few volts when ever I insert one of the three fuses, note that the DC_Outlet causes the voltage drop only when there is a load in the 12V outlet which is logical.

The key switched Vbat line only goes to these fuses and the EPS module, and I disconnected the EPS module, so it would seem that the issue is somewhere from the key switch to the fuse box for these three fuses.  My next test will be to remove the key switched Vbat line to the three fuses, and jumping in power to those fuses, although that might be quite tricky as the fuse box doesn't come out very far.

With the three fuses removed Vbat seems to be fine, why wouldn't I get anything on the display with the Light/Control_Signal/DC_Outlet fuses removed?  I'm not sure where the display gets it's power from, but it lights up for a few seconds when I first connect the battery.

Thoughts @NMKawierider?

[NMKawierider]

Possibly the problem is even before the key switch. From 2018-2021 on most models CFM had a problem with the main fuse holder itself in that hundreds had bad internal crimps that would open or near-open with loads applied. This would not blow the fuse. Put it all back together and test the battery power at the battery. Then probe both wires on the fuse. They may all be the same with the key off. Then turn the key on and turn the head lights on...then probe both main fuse wires again. If you fine one very much lower then the other...the other being the battery side...you have your answer. Some were so bad they even showed melting on the sides. 

[Birchy]

I'm not sure which is the main fuse, the 40A or 50A, so I tested and tried removing both but the issue remained.

So I returned my focus to the 30A starter module.  I took it apart again (I had cleaned it up previously after seeing that it had slightly melted and the fuse was blown), gave it a good wiggle and low & behold, it worked - dash came up and the bike started - YEAH!

So I would think that replacing that module is a good idea.

Thanks very much for your assistance, how can I buy you a few beers?
Cheers
  John

[NMKawierider]

Sounds like you found it. Good for you.