2008 Te450 Dashboard Electrical Gremlin

Has anyone had an issue/ odd behavior with their Dashboard/ Tach / Instrument causing an electrical drain and potentially resulting starting issues?

Issue: When I pull the negative from the battery and drain test, I get a reading of around 1.6mA, until I pull the connector going into the Dash, then it reads 0 as expected. The dash itself works fine when plugged in, however, if I leave the dash plugged in it has trouble starting - it cranks and cranks, but won't fire - the battery quickly gets fully drained when doing this. I've been able to jumpstart it when the dash is plugged in, but then it starts to run rough after it gets warm.
With the dash not connected, it seems to start up and run fine (although it has been requiring a bit of throttle to get it to fire, and has always required a bit of manual decomp lever since I've owned the bike).

Question 1: Does anyone have any advice on how to resolve the dashboard electrical issue? More specifically - does it sound like something inside the dashboard is toast, or is it more likely that one of the wires leading into the dash is the issue? I've gone through all the wires (visually) and cut half of the wiring harness apart at this point, but haven't found anything. Perhaps I should start by pulling/ disabling the 9 wires going into the dash one at a time and see if there is a single one that eradicates the drain?

Question 2: Could the electrical drain be causing the starting issue, or is that probably something else?

Attached electrical diagram for reference.

Re-attaching the electrical diagram for better clarity

Small update - I purchased one of those electrical connector pin removal kits so I could back out the wires from the connector that fits into the dash/ tach. When removing the yellow/ black wire, the amp draw goes away completely. None of the other wires showed any draw.

From the wiring diagram, The YB wire is connected to the dash/tach, DC relay, flasher relay, main (ignition) switch, and the yellow 20 amp fuse next to the battery. So I guess I need to trace the wire to see if it's damaged/ shorting anywhere. the majority of it is encapsulated in the thick rubber insulation of the wiring harness so hopefully I won't have to cut that open. Will report back with progress.

Some updates:

1) Purchased a new dash - the one I got was a brand new take off in perfect condition - unfortunately same issue. I had a feeling that would be the case, but hadn't tried pay and pray on anything yet and needed some other parts it came with so

2) Cut away the wiring harness so that I could follow the Yellow Black - haven't been able to find any obvious issues. I did remove all the other accessories connected to the yellow black wire to confirm again that nothing else seems to be affecting it. The Yellow Black wire that splits in the middle of the harness. The wire that goes into the dash from the split is thinner gauge than the rest, making it a little easier to follow, but still not seeing anything. Pushing and moving the wire around including where the split occurs didn't produce any change in the electrical draw.

3) I realized that the electrical diagram shows 10 connections into the dashboard, but there are 13 wires going into it. Not sure if I have the wrong wiring diagram - I've been using the 09 workshop manual as its the only thing I was able to find online.

Feeling pretty stumped, but will cut the rest of the wiring harness apart tomorrow and take a look at the split/ intersection of the yellow black for damage.

Spent some more time "tinkering." It appears that the blue wire going into the dash also has something to do with the equation. If I take the blue wire/ pin out from the dash, the drain also goes away. Since the blue wire is the negative, I assume its just necessary to complete the circuit - so now I am second guessing if the yellow black, which I think is just the positive/ power, is actually the culprit. I followed the blue from the dash everywhere, not seeing anything that looks off. The blue goes from the dash to ground at the ignition coil - if I pull the ground from the ignition coil, the drain also goes away. I'll admit I haven't cut every single piece of heat shrink around the wires in question yet, but they all look good, so I'd be surprised if the issue was a wire encased in them.

Not sure how to move forward, may just need to find a second pair of eyes.

You may already have done this but when doing your drain test disconnect the connector for the Light / turn signal / horn switch. If you still have the drain then pull the dc relay. If you still have the drain disconnect the connector for the main switch. If you still have the drain pull the fan relay.

Thanks for the reply Mysery. I have tried this. Aside from the dashboard, I currently have every accessory that the yellow-black wire feeds disconnected - main switch (ignition), DC relay and fan relay. I also have every other accessory that connects into the dash disconnected - lights, blinkers, LH switch, ECU, horn, speed sensor, fuel pump, etc.

If I disconnect the dash, the draw goes away, or if I disconnect the 20 amp fuse, the draw goes away. The 20 amp fuse pairs a yellow-black and a yellow-red wire. The yellow-red goes exclusively to the voltage regulator - if I leave the fuse in and disconnect the voltage regulator, the drain is still there. It surprises me that disconnecting the voltage regulator does not also result in the drain going away, since it exclusively goes to the voltage regulator (no splits along the way) and thus I thought disconnecting it would break the circuit. Perhaps that is a queue?

Today I cut the rest of the wiring harness apart. I noticed the portion of the harness that is above the exhaust is pretty hard/ not flexible like the other parts of the wiring harness, but there doesn't appear to by any damage to any of the wires. Flexing the wires where they are hard doesn't change the draw.

I also tried pulling the yellow black and blue pin (blue negative, not the turn signal pin which is also blue) from the dashboard connector and clipping them together - I'm not sure if this is a correct way to test whether the drain is coming from the dash itself, but when I do this the draw is still there.

Spent some more time following wires around, and figured out why unplugging the voltage regulator didn’t result in eradicating the draw - the red yellow wire that goes from the 20a fuse to it shares a pin with a red wire that comes directly and exclusively from the electronic start relay (they are crimped to a single connector).

This made me look at the starter relay as well as the red wire. Unfortunately, nothing notable. Even took the red wire/ pin out from the electronic start relay and connected it directly to the battery to bypass the relay, and still shows the draw.

So at this point I think I may have exceeded my electrical capabilities and understanding of what to try next. The most suspicious thing I’ve found is how hard / stiff some of the wires are around the exhaust and other hit areas. Flexing those areas didn’t seem to make any changes in the draw, but i’m not an expert so i’m not sure if that is a reliable test.