Topic: CB500k2 brake light/tail light running light issue

[LastChancer88]

So I'll start by saying all the signals on my '73 CB500 four are aftermarket and I know the PO donked some stuff up, but I figure someone can still help me because it's pretty close to stock minus the tail light.  Still uses the original harness.

 So right now when the key is ON and the headlight is turned to LOW the headlight and all the turn signals come on but not the tail light.  The tail light works when you press either brake down which is great, but I'd like to have the brake as the running light and the signals as only on when needed.    The easiest way I think to answer my question is if anyone can tell me for sure which wire is the "running light" for the tail light.  My three different manuals (2x online honda, Clymer in hand) say it should be three wires to the tail light which are Dark Green, Green/Yellow, and Brown.  The Brown wire looks like it goes to the Main Switch which I would guess to be the running light?  The Green/Yellow goes to the Front Stop switch aka when you press the brake?  Dark Green should be the ground then as it connects to the turn signals? 

The tail light only has two wires built on but I assume it grounds to its housing and the bracket.  It's one of those aftermarket cat eye brake lights from 4into1.  If anyone has wired one of these and can help that would be ace!

[69cb750]

Green is ground
Brown is tail light
Green/Yellow is brake light
Add a ground wire from tail light to harness

[LastChancer88]

Looks like I'm going to have to pull the tank off and go over the whole harness.  There's a wire that looks like it was added after the fact outside the harness running to the front, and the front turn signals still come on as running lights.  I wasn't able to get the light to come on for a running light so I'll be removing the cover to check the bulb as well.  Pics will follow.  I may port this over to a project thread for this bike, despite it being a complete bike it is definitely an ongoing project. 

Thanks for the clarification!

[LastChancer88]

Update:  All turn signals now function as only turn signals!  Hooray.  The tail light is still not working though the brake light does.  The bulb looked good.  I tried adding a ground wire to it and still no running tail light.  It was a dual filament bulb so it should work as a running light too correct?  I'll try to take some pics this evening.

https://4into1.com/large-cat-eye-tail-light-assembly/

^^that's the light.  The description says 3 wires but the picture clearly shows only 2 which is what mine has.