1978 Kawasaki KZ400 Fuse Short (?) and Blinker Issues Question

We'll focus on the connector in the red circle. First we will check the blinkers then the blue wire short. Funny enough, all of these issues could be in your left handlebar multi-switch.

Anyway,
Take out the blue wire fuse.

Meter on DC V
Key switch on
kill switch set to off
engine not running

Black probe on battery negative post.
Leave that red circle connector connected. The readings will not be correct if it is disconnected.
Red probe is going to backprobe the orange wire on both side of the connector..
The reading should be close to battery voltage on both sides.

Switch the turn signal switch to the left.
Back probe with the Red probe the green and grey wires both sides of the connector.
Green should see 12v on both sides.
Grey should be close to 0.0V

switch turn signal to the right
red probe green and grey wires again.
readings should be reversed
grey close to 12v
green close to 0.0v

disconnect the connector in the red circle
disconnect headlight connector
black probe on battery positive post
red probe blue wire at one side of the connector.
reading should be 0.0v fluctuating.

red probe the blue wire on the other side of the connector
remember this connector should be disconnected at this point.
reading should be 0.0v fluctuating.
Wherever you saw a much higher voltage than 0.0v, that will be the blue wire section with the short.


turn off bike
red probe

Backprobing may require a needle, nail, paperclip ifbyour probes are too short.

Okay so! Interesting day. Some good and some bad, 

I changed one of the ground posts just to brute force test it. The PO had said that he had given up on the blinker issue, which I naively assumed meant it was complicated, so I glanced over some of the obvious spots, which would have saved me quite the headache as I'm guessing "giving up" meant the blinkers stopped working and he just... didn't care. The light wire was disconnected in the switch. Five minute fix and the blinkers were back up again. Everything ran great, I changed the oil real quick and reassembled everything. Still missing the tach and speedo lights, but I'll get those replaced before I make any firm ascertations. 

I walked it to the road for a ride and hit a tree root. I managed to recover it before it fell fully, but by the time it was back up the starter motor was having a realll rough time and I figured out that the battery had dropped to 6v. Couldn't get it to kickstart either. All sorts of indicators and circuits were malfunctioning, including the blinkers, it seems, but I'm charging the battery, hoping I didn't permanently screw anything up, putting a replacement battery in my online shopping cart, and hoping for the best when I reconnect it tomorrow. None of the fuses are blown, so I at least didn't short anything out. Hopefully. 

The blue wire short did appear to be in the multi-switch as well. After I got everything settled in there, I blew a couple of the fuses before I went back in there and re-straightened things out. Headlight worked wonderfully after that. 

Sometimes it just feels like when I finally get something working, several more things decide they no longer want to. Please, Adeline, I just need to get to work and back!

It didn't fall fully, and there was no real impact, so would any of that affect the electricals asides from the battery in any meaningful capacity? I know the batteries aren't solid state and this one may very well need replaced, but from your experience should that really affect anything else?

F64 is offering his expertise and experience in diagnostics. If you do not want his help, just say so, so he can move on with his life.
By changing some ground wire you may have introduced yet another problem.
If the battery fell from more than 12 volts to only 6 volts in the time it took to walk to the road, there is a serious drain someplace. 
If you carefully follow F64’s instructions, he will lead you to all of the problems.

I'm sorry! I didn't mean to seem like I wasn't appreciative of his help. I was just a little out of step with what was up on the forum and the tests I was still running; I was still following the brown wire and it's peripherals like Wookie had advised by the time I saw the new posts. In any case, I had solved both of my original problems in the same place that F64 was eventually trying to lead me towards.

I realize and deeply appreciate that anyone replying to this forum to help me out is taking time and resources out of their day to do so. If anyone feels like their time is wasted here, I more than understand wanting to move on and spend your time elsewhere. I'm brand new and hearing all of this for the first time, and I'm definitely making my share of mistakes, so I understand if that's frustrating to work with. That said, I have learned a lot and will definitely be better equipped to deal with related issues in the future. For now, it's kind of all really overwhelming but we're working through it.

As for the current issues, it's not really related to this specific thread; I just posted the last update to see if anyone knew of any precedent for electrical or starter motor failures after a stationary fall. Again, I'm trying to do research and look through manuals on my own but I'm also really trying to have all my bases covered. Since both of my original problems were resolved, I'm currently considering this thread closed.

As for the possibility of a new ground issue, I'm 98% sure not; I only swapped around some hardware for the left blinker, left the right untouched as a control, and when the switch was fixed both ran identically, so that had seemingly nothing to do with the blinker issue.

As for the battery, I know the half-fall definitely messed something up. I figured that the battery that says "do not tip" in bold on the side probably doesn't play well when it... You know, tips. Isn't charging either, so we'll have to figure something out.

Thanks everyone! I'll try my best to figure it out from here.
 

Apologies F64 if my input caused any confusion

No worries. Too often we see a newbie ask for help, then run out of patience and starts jumping from one thing to another, never getting to the problem. 

No worries Wookie. Sometimes it's good to work on things together. Helps to have an extra set of eyes.
Thanks TexasKZ.