HELP! Entire vehicles voltage goes crazy when music playing at any volume!!!!!!!!!!!!

[fbi90909 5,000+ posts]

the lowdown:

today i began helping a friend of mine run a Big 3 and run 1/0GA wire to the back of his 2001 ford escape to hook up 2 kenwood kac-7203.

here's how my wiring is. 1/0 battery to fuse, to trunk, to Knu 1/0ga in to 2x 4ga out fused distro block, 4ga to each amp. then each amp is 4ga ground to frame.

i used the existing remote wire that was already run in the car. also used the existing RCA's that were in the car.

well i sold him my red top and we also switched out the batteries.

here's where i started to notice a problem.

when we first turned the Radio on(car off) everything turned on fine. he then puts on a cd at a very low volume(i.e level 5 out of 30). with that he shows me dimming that happens in his car. now this is the dash, the head lights, the fog lights, and even the amps are flickering like they are getting a shortage of power.

i think wtf???

i take my multimeter and read at the battery and voltage is jumping around like crazy. so i'm like wtf again.

i ask him to pause the music. and the voltage stops jumping and stabalizes itself. so i'm thinking somethings wrong with the wiring of the head unit.

though i have no clue what would cause this. now this is like every little bass note and the lights would just dim BAD. and the music isn't even turned up! shit the amps gains haven't even been set and were set to nothing and the lights were dimming.

i also noticed that only having the system on for 30 minutes and having nothing set while trying to figure this issue all out i find the amps were getting really hot.. i mean HOT. could this be my ground not being suffecient?(i know how to properly prep a ground).

he told me that the initial system that was installed int he car was installed at a best buy, and since then he has had that dimming issue.(i have a strong feeling they ****ed up)

he currently runs one of those motorized kenwood touch screens,but it's a recent HU. he had a different HU installed before and had the same dimming issue.

if you have any guess as to what could cause this please just post a message. i will begin to work on the car again tomorrow after work so while i'm at work i can check the forum and ask questions.

thanks yous anyone?

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[ThatChevyGuy 5,000+ posts]

Wow can't touch this one.

Maybe something to do with the car brain.

 

[dragnix 5,000+ posts]

check the ground?

 

[DD_Dave 10+ year member]

The same thing usually happens when you hook up a pair of Funky Pups //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[fbi90909 5,000+ posts]

OOOOO on a side note. i can't say if this could be affecting the voltage BUT the vehicle has an aftermarket alarm, door poppers, fog lights,. i believe that's it for aftermarket parts that consist with the electrical. though i dont' think any of those have anything to do with how the vehicle is reacting.

 

[ThatChevyGuy 5,000+ posts]

I still say computer/brain

 

[fbi90909 5,000+ posts]

I still say computer/brain

but H.U to the computer/brain?

i feel it's something wired incorrectly behind the HU that is causeing this. because the only way i see it is the wires that would go thru the brain and to the HU are the ACC,BATTERY, and GROUND. every other wire can be bypassed and run direct.

actually every wire can be run direct if you take the time to actually run all the wires direct to source and bypass the entire computer/brain.

still i just don't see how any musical note would cause the entire electrical to go nuts.

 

[fbi90909 5,000+ posts]

i need to go to bed. i need to wake up in 5 hours.

 

[ThatChevyGuy 5,000+ posts]

voltage regulator or something in the computer/brain malfunctioning?

 

[fbi90909 5,000+ posts]

bump, any thoughts anyone?

 

[dman4486 5,000+ posts]

I have a thought!

why do people call it a brain...it is a computer

 

[rich52490 10+ year member]

People refer to it as a brain because it runs the entire car. It's responsible for making all the decisions.

For example, the human brain controls all of our bodily functions.

 

[jco1385 5,000+ posts]

re-wire the HU, and make sure there is nothing grounding out on the frame or any sheetmetal

 

[fwb_1234 10+ year member]

Hey check the voltage across the power connectors of the amp with no music playing. Car on, but silence. Make sure it's the same as the drop across the bat. terminals.

 

[fbi90909 5,000+ posts]

re-wire the HU, and make sure there is nothing grounding out on the frame or any sheetmetal

i had put that in mind. i'm going to pull out the head unit today and take a look at how everything is wired. i'm just hoping to not find a rats nest back there. or spliced factory wire harness and unlabeled wires.

he still has his factory radio so i'm going to try to plug that in so i can run another test on it. if it runs fine then i can either break it down to being the wiring or the head unit itself causing some sort of short.

i have an extra harness for my civic that i can take his head unit and temp wire it to my vehicle to and see if it could be the head unit itself.

the drop at the terminals of the amps is the same as the battery. it's all new runs of wire 1/0. it used to be 4ga but it was removed to support the 2 amps.

i'm not sure if i clearly mentioned it but when i stopped the music and found the voltage stabalize i had pressed Pause. today i'll try with setting the music at like level 1. to see if does the same thing.

i dono. lol, and all i was supposed to do was just run new power wire and big 3.

i'm going to have to say this is probably the last car i will work on that is not mine. people want their cars setup i'l make them sign release forms or some shit lol.