decent light dimming with bass, checking grounds?

[mwjames]

So i'm suspecting the grounds running to my amp and cap aren't the greatest as i get a decent amount of headlight dimming when i turn the stereo up to a decent volume and I am running less then 1,000 rms. my battery could probably use replacing soon but i would like to check through my grounds. The car's a 98 monte carlo i think the alternator is 105 amp.

I currently have the big 3 done with 4 gauge, I'm running 4gauge back to the cap then to amp. The amp and cap are both grounded to the seatbelt bolts under the back seat. I scraped off the paint and such from around the bolts I didn't put a terminal on the wire though, It's just a bunch of wire wrapped around the bolt then held down by a nut.

So they main part of why I am posting is because I know there is a wait to check the grounds with a multimeter but I am unsure of how to go about doing this. If somebody could post how, that would be awesome it would be a bit better if you could post it in simple english to somebody who hasn't used the multimeter much

Also when i check the grounds with the meter should i have the car running with the system going?

I'm a novice at best with car audio, the amp is a class D monoblock alpine incase that helps at all.

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[solidcrowd 10+ year member]

I don't think seatbelt bolts are a good ground to begin with. Ground should be attached to the frame of the car.

 

[jsluss17 10+ year member]

take the capacitor out and you'll see a difference

 

[mwjames]

I would think the seat belt bolts would be a decent place to put the ground, the wires touching the metal of the car and the seat belt bolt should be something that would be ran in a sturdy chunk of metal from the factory. Do you have any other suggestions of were to mount the ground?

I've noticed a very slight reduction with the capacitor so I figure I minds well leave it in. I know they don't hold much power but why not use it if i already have, it's a slight improvement.

Anybody got input of how to check the grounds with my multimeter? what setting should it be on, what should it read?

 

[mwjames]

nevermind i figured out how to test the grounds, I'll let ya know whether or not my current grounds are any good at all when i check them.

Thanks for the help!

 

[IonRL205 10+ year member]

nevermind i figured out how to test the grounds, I'll let ya know whether or not my current grounds are any good at all when i check them.
Thanks for the help!

i doubt your grounds are the problem.

Seems more like your battery. How old is it?

The battery may just be losing it's charge and your amp is ******* out the last of it every time the bass hits, which would be why your lights are dimming; they aren't getting proper voltage.

 

[goingdef 10+ year member]

you want to check for ohm loads if your checking grounds it's all about the resistance you want as low a number as possible.

 

[VisceralSound 10+ year member]

Delete capacitor too.

 

[solidcrowd 10+ year member]

Might be different for all cars...seatbelt bolts in my car were not a good choice.. How about one of the bolts that holds your back strut in the trunk?

 

[Mitch86 5,000+ posts]

Put a ring terminal on that wire!

 

[mwjames]

ok so i checked the grounds all read .04 on a 200ohm scale which was the same as putting the 2 points of the DMM together. I don't know how old the battery is in my car i've had the car for a little over 6 months. Why's everybody so passionate on removing the cap, I know they don't hold much juice but why else delete it?

 

[goingdef 10+ year member]

A cap is designed to simply eliminate voltage ripples in set-up that's not proper it hinders the voltage it doesn't help it.

 

[goingdef 10+ year member]

also you have a dmm what kind of drops are we talking about?

 

[mwjames]

I have not checked the drops with the dmm, but the lowest i've seen it drop is to 12.8 volts according to the capacitor readings. but i don't like to let it drop lower then 13. I'll take the cap out and see how that goes. Thanks for the input so far I appreciate it //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif