I think I'm shorting out somewhere. But where??

[dat LS2 rx7]

Ok so I'll explain my wiring issue as best I can. Started off one day my radio seemed to just randomly keep shutting off and starting back up. Later I traced the cause to be whenever I'd press the brak pedal. Once it got dark out I realized that pressing the brakes also causes all my lights to dim down as well as my temp gauge to read that it's overheating. Then I found out that my headlights also contributed to making the gauge move up higher. But one thing I noticed is that the problem is a lot less bad when I'm not moving. I've looked around for a problem similar to this with no luck. Cars a 92 S13 with a blacktop SR if that matters. Any help is greatly appreciated. I'll post a video in a sec

[jr_ss]

How low are you? Possible rub through on the harness.

[Link]

id like to know how this goes. my speakers randomly go off/on at the press of the brake pedal.

[inopsey]

what voltage is your alternator putting out

[Croustibat]

Just change your harness, or get ready to spend countless hours looking for a short somewhere (you may never find it)

[dat LS2 rx7]

I'm not rubbing through my harness, I thought it was that as well but I've tucked them on both sides. I'll check ALT voltage in the morning. It should just be like 12v right?

[fliprayzin240sx]

No, you should be seeing closer to 14v when the engine/alternator is running.

[dat LS2 rx7]

No, you should be seeing closer to 14v when the engine/alternator is running.

Alright thanks.

Also, popped my rad cap and realized there's no water in there. But I checked to see if my HG was blown and it seems ok (I've rebuilt my motor already and have a cosworth metal HG)
But this shouldn't cause the light dimming and shorting on the radio.

Also double Checked the fender harness's. they're ok.

Right now I'm pulling my dash and checking back there but so far no sign of what the issue is

[dat LS2 rx7]

Ok im probably going to purchase a new engine harness and hope to god that that fixes it. (even if not, i really needed to replace mine)

[dat LS2 rx7]

so now my tachometer isnt working, im getting the thought that my gauge cluster could be the culprit? but not totally sure. still really could use some help