alright so here is my situation. going from the stock 02 headunit to a pioneer touch screen p2300dvd headunit. the first time i wired it up i shorted it out, i believe because i had 1/3 grounds hooked up and it turned on when key was on ACC but then turned when turning key off then back on to try to make sure HU lit up again fuse blew and it didnt go on. At that time i only had the wiring harness ground connected. So went home, replaced the fus in engine bay 15A that controls the clock, radio, dome and map lights. Also when that fuse was blown it would reset my trip mileage back to 0 each time turned car off/on. So checked all my wires. Constant power wire to the harness has power, grounds work, ACC power works fine when turning key on. used a test light for all that. speaker wires are all wired up in the harness fine. have the one ground is the stock wiring harness, the other is a little black clip that goes on the headunit metal bracket that goes around the headunit itself, and the third goes through a screw against the metal headunit bracket. so radio works, radio plays. turns off and on with out blowing fuses butttt when on ACC and i have the radio on its fine, but when i turn the headlights on the radio turns off and a loud screeching steady noise comes thorugh the speaker. Sounds kinda like a door alarm like when your door isnt closed but its a continuous steady screeching. So if headlights are on radio stops playing, but doesnt turn off, still works just no sound, the screeching noise is head and then if u turn the dash illumination control all the way to dim the screeching stops but still doesnt play sound. I have not tried if it screeches when running but shouldnt make weird noises at all so i know somethings wrong. figured it had to do with the radio illumination light. checked all fuses and theyre fine....so just trying to figure out what this is..
-grounds and power wires are correct.
-speaker wires correct
-stock sub not connected ( no need to yet, want to make sure HU correctly works)
-ACC power HU plays and normal
-ACC power with headlights on, no music, makes a screeching sound.
-ACC power with headlights on dimmer down to low, no music, no screeching sound.
so going back to recheck and everything and try to figure out where this little screeching gremlin is hiding.