factory subwoofer dims lights

[matt]

I have an 02 WRX with the 6 disc cd changer and factory subwoofer. When i
turn on my dome light the sub woofer dims it during a kickdrum in the song.
I never thought that sub was very loud, so why is it dimming the lights? a
week ago i got a new battery because the original one died, so i figured
that would fix it, but after looking at it again, it's still dimming. I
hear people talking about the weak alternator and it only being 75 watts,
but could that be the problem? The technition that replaced my battery
checked the alternator and said it's fine. Also, i hear people talking
about installing sound systems and using a capacitor to buffer some current.
Would i really need that for the factory subwoofer?

Thanks for any clues!

 

[Carl 1 Lucky Texan]

I would clean and re-tighten as many ground connections as possible. A
lot pf electrical problems ca be traced to poor or rusty ground conns.
just a thought

Carl

 

[Mark jb]

I would clean and re-tighten as many ground connections as possible. A

lot pf electrical problems ca be traced to poor or rusty ground conns.
just a thought

nar, it's pulling too much power for the alternator.

you can get a one-farad capacitor and wire it in as close to the amp as
possible, but it's only really useful in high-power applications. wouldn't
be worth the cost in an oem setup.

perhaps not drive with the dome light on? or turn the sound down when you
stop?

you could always get a better alternator if you want to fix it once and for
all... but hell, my toyota starlet alternator can handle 600 watts of audio,
400 watts of lighting and whatever it takes for the car to 'go' all at once.
without things dimming, etc.

could be the way the factory amp is wired. if it's run off the accessories,
instead of straight off the battery with a 'signal' wire to turn it on and
off, it could be pulling too much off the acc. wiring without going so far
as to blow the fuse.

-mark

 

[l.lichtman]

clip) When i

turn on my dome light the sub woofer dims it during a kickdrum in the song. (clip) Thanks for any clues!

^^^^^^^^^^^^^^^^^^^
I doubt it is the alternator. You should be able to listen to your
audio/radio while parked, with the engine off. Either your battery
can't handle the current draw of the amplifier during big power peaks,
or there is a resistance somewhere in the wiring, causing a voltage
drop, affecting the dome light and the amplifier. I would check by
hooking a voltmeter directly to the battery, and playing the kickdrum
thing. If you see voltage fluctuations there, it's the battery. If
not, it's in the wiring. If you don't have a meter, you could use a
light bulb, similar in size to the dome light, and see whether it dims.

If it's the battery, then the question is: Is the battery too small
for the kickdrums, or is it losing capacity because it is several years
old, and near the end of its life?

If it's no6t the battery, then you have the chore of finding a bad
connection in the wiring. Short of just going around wiggling things,
that can be a challenging task, since the wiring goes all over the
place, including under the dash, and inside harnesses. You might be
smart to just live with the "problem." Do you listen to kickdrums a
lot with the dome light on?

 

[Bryan Lee]

I had the same thing happen in my '04 WRX wagon. The odd thing is after I
pulled the stock sub. I kept the stock head unit. I added sirius sat.
radio, 100w x 4 amp to run my pioneer 3-way 6.5"s in the door and added a
150w mono amp to run the 10" Fosgate P1 sub I mounted in the floor. Now the
light does not dim. I think the stock sub amp is just not very good and
draws alot of power.

 

[nothermark]

clip) When i
^^^^^^^^^^^^^^^^^^^
I doubt it is the alternator. You should be able to listen to your
audio/radio while parked, with the engine off. Either your battery
can't handle the current draw of the amplifier during big power peaks,
or there is a resistance somewhere in the wiring, causing a voltage
drop, affecting the dome light and the amplifier. I would check by
hooking a voltmeter directly to the battery, and playing the kickdrum
thing. If you see voltage fluctuations there, it's the battery. If
not, it's in the wiring. If you don't have a meter, you could use a
light bulb, similar in size to the dome light, and see whether it dims.

If it's the battery, then the question is: Is the battery too small
for the kickdrums, or is it losing capacity because it is several years
old, and near the end of its life?

If it's no6t the battery, then you have the chore of finding a bad
connection in the wiring. Short of just going around wiggling things,
that can be a challenging task, since the wiring goes all over the
place, including under the dash, and inside harnesses. You might be
smart to just live with the "problem." Do you listen to kickdrums a
lot with the dome light on?

If you are sitting idling with the dome light and stereo on be aware
that the alternator is *not* putting out anywhere near rated output at
idle. If you take the engine up to 2500 RPM does it still happen?