headlights dimming , cap on

A friend just bought a new truck; its a 2008 chevy silverado crew cab. Of course all new toys need more base and so weve installed a small system that sounds good; but somehow are still running into the general problem of his headlights dimming. The system is extremely basic and simple: 2ea Kicker CVT 12s, Power Acoustik BAMF 1800/2, 5 farad PA CAP in an aftermarket box fitted for the truck. I have done basic car audio before and am an electrican by trade, so figured it would be easy but am now baffeled and need assitance. Speakers are 400w RMS & 800w peak, so the amp is more than enough for them. Wiring was kept seperate, 1 speaker per channel, and the cap is mounted right in front of amp so wires are as short as possible. The base control knob that came with the amp doesnt seem to work so we just took it out of the system. And the third problem is the that the amp stays on constantly. After we shut the truck off, it will recharge back to around 14v but it stays lit up and we assume that its drainging off the battery. Any help with these problems would be greatly appreciated.

I didn't even read it. You wanna know why? Because a CAP IS NOT YOUR ANSWER! Period. Went to BestBuy, huh? You need a high output alternator. End of story. Start lookin'.

Move the cap to the headlights instead. Otherwise there are lot of other threads about bigger alternators, second batteries, Big-3, low resistance cabling etc. And even about using $20 batteries instead of 5F & 8F caps.

lose the cap. upgrade the battery under the hood. if the amp is staying on then you have the remote wire hooked to a constant 12v source so what did you hook it to? make sure all of your ground wires are as short as possible, screwed tightly to bare metal with all paint and primer sanded off. a seat belt bolt is not a good ground. make sure the wire is appropriately sized for the current draw of the amp, at least a true 4 gauge. if after all of this the lights still dim, then i would chalk it up to it being a chevy truck because chevys have the most garbage electrical system out of any vehicle that i usually work on.

Hey SnS - The Chevy LUV was ok! LOL - A former soldier "talked" to me about driving a Jap car. He had a "Chevy" LUV! rscwboy - keep in mind that the battery type & size remote from the surging amp has little effect unless extreme cables are used. That's why an additional (AGM) battery is collocated with the amp. Those that have a remote battery are conned into buying caps to compensate, but even then, a small AGM instead is better (ie, is smaller than the cap, is cheaper, and lasts far longer). Extra batteries are not to make up for undersized alternator. An undersized alternator not only means battery flattening, but usually 2 Volts LESS to the amplifier (eg - 14.4V vs 12.4V - not that that should make a difference!)

what is a chevy LUV? light utility vehicle?

I h8 u SnS - it took me decades to figure that out!!! Yes - a rebadged Isuzu from early 1970s onwards. Often wins engine blow-up competitions (valve bounce, no oil or coolant). It was the ute (pick-up) version of the Isuzu "Florian" - later Aska, SAAB etc with offshoots (like the 117 coupe). The LUV became the KB-series and then Rodeo. People here pay a fortune for them because they think they are "Chevrolet". Blame GM for that!

hahaha, awesome. good info.

You have the amp's remote terminal connected to a constant 12 volt source.  You should be able to find a switched power source to turn the amp on only when the Ignition is powered up.  Check the fuse in the top right corner of the fusebox that is located on the left end of the dash.   This information may or may not be for the 2008 model.  You will need to check it.

rscwboy, if you have gotten this far, I'd like to apologize for... well... SOME of our responses, especially the jabs (and there might be another here...), were you to have taken any of our responses as such... Anyway. You really need to ditch the cap, and address the failure of your electrical system. ALL of the electrical power for a car (when running) comes from the alternator; thus my reference to "the failure". If your alternator is too small (potentially indicated by dimming lights, as in your particular case), this is a sure sign you need a larger one. OEM is undersized almost from the factory, let alone adding an additional 150A load from an "amp". Yep... I already KNEW is was an E-swooswoo, but here's a little more info, re: Chevy LUV... To echo soundnsecurity, ALL of the Chevy electrical systems are complete and total garbage. A 200,000 mile motor (OK, a 100,000 mile motor) with a 25,000 mile/three year alternator (or a 35,000 mile tranny (check the forums...), whichever comes first - YMMV - :P). Seriously, ANYTHING you can do to beef the overall system, you will be MILES ahead. This includes AFTERMARKET (as in NOT OEM) high output alternator, all new wires, and a better battery. Wax all of the underhood stuff, and re-wire it properly.