Dimming of dash and other lights when turn signal is used

[arcster0101]

Here's the problem thats been bugging me since I noticed it (first time I took the bike out at night):
I signal right, the right signals get bright and everything else dims. Headlights, the other signal, plate light, dash and brake light.
Same thing with the left signal,
Same thing when I apply the break!

Disconnected the headlights and brake light, signaled and still dims the dash and the opposite signal.


What I tried:
1) Replace battery. Battery was a strong 12.9v but new battery stays at 13.4v...no change (salty because money but whatever)
2) Replaced the rectifier regulator. Swapped it out, no change. (returned it, kept oem)
3) MAYBE ITS THE ALTERNATOR??? nope, turn on the bike, checked the voltage 14v+ its good.

Now my last guess: It's either a bad ground or a relay.
I was looking into that flasher relay everyone here uses but I couldnt find the one from superbrightleds.com (link me pls and I idk where that thread is on what to do and how it works. I just see people talk about it.

Any help is appreciated!
Oh, yea this is an issue for me because I personally feel like my bike looks cheap with the damn headlight dimming when I signal. Like... it just looks dumb trust me.
Nothing mechanically wrong but just a damn eyesore.

 

[FinalImpact]

Sounds like the later steps are nearing the target. I would begin by pulling the connections apart and inspecting them. In this case the left inner fairing cover comes off and look for burns, discoloration, green corrosion.

These: mid right and bottom pic, bottom left.

If after inspecting this you find nothing now its going to be a bit more difficult. But before we go there, pull the headlight bulbs and give them a thorough inspection. Confim you don't have some crazy 100watt light in there or a shorted element.

Do you have a hand held meter? If not, you need one that can measure volts and ohms. One option is to ohm the headlight black wire resistance back to the battery Negative terminal. It should read Zero ohms. Verify this.

The other option when the bike is assembled is to use the volt meter and verify where the system is dropping voltage.
Measure battery voltage bike running. Record value.
Back probe headlights for voltage. Record value. This should be very close to battery voltage.

Now move your test leads and measure voltage drop of the ground wire by leaving one probe on the (-) side of the lamp and place the other on (-) battery terminal. In the ideal world you meter will remain at zero volts. Repeat this same test on the (+) lamp to (+) battery terminal. Any voltage seen is loss do to resistance. Our concern is likely on the ground side. If more than say (guessing) 0.25volts you need to find the fault or bad connection as it could be a fire hazard. Mind you this hazard will not pop a fuse but could burn anyway until a direct short occurs and then the fuse pops.

If you need to inspect further, lift the tank and remove the battery and airbox. You need to follow the lighting harness back to the main harness and inspect that. With the right tools it is a 15" job to get there.

Let us know what you find. Good luck.