Car shorting out need HELP please starting to worry me

[drumminian]

Okay I drive a 1997 toyota tercel..

stock alt, big 3 upgrade, yellow top, bp1200.1 amp, on a fi BL.

Okay so this is a weird problem I have been having, while driving whenever I either press the brake/turn signals/headlights, my headunit will turn off and back on again. I haven't been able to figure out what it was thought it was the ground for the headunit but that wasn't it.

what all should I check?

I also get pretty low voltage randomly like <12 sitting idle and even driving with no bass heavy music playing. And the car somethings seems if the battery gets unconnected when I start it like i put th key in turn and as soon as the engine starts to crank I loose power....

very weird I need your help smd

[Gotloud555]

Okay I drive a 1997 toyota tercel..

stock alt, big 3 upgrade, yellow top, bp1200.1 amp, on a fi BL.

Okay so this is a weird problem I have been having, while driving whenever I either press the brake/turn signals/headlights, my headunit will turn off and back on again. I haven't been able to figure out what it was thought it was the ground for the headunit but that wasn't it.

what all should I check?

I also get pretty low voltage randomly like <12 sitting idle and even driving with no bass heavy music playing. And the car somethings seems if the battery gets unconnected when I start it like i put th key in turn and as soon as the engine starts to crank I loose power....

very weird I need your help smd

Did you had this problem before you did big 3 or any electrical upgrade? Having that low voltage bad for the vehicle feul pump. How's the condition of the battery and connection on the alternator?