OK, my story...
I bought a 2003 GS300 about a year ago. Shortly after I bought it, I had a local audio shop remove the factory head unit and install a Jensen flip-up DVD player, 2 Fosgate 10" subwoofers and a 900 watt Jensen amp. Everything worked great for a couple months. Then, the subwoofers started shutting down after they would play for a while. Then, I started noticing that the headlights and a/c fan would dim/slow at idle (the lights/a/c fan would return to full power when RPMs were above idle). Finally, the whole stereo system started shutting down after it would play at high volume for a time (ranging from 2 minutes to 15 minutes). When the whole system shuts down, it usually powers back on within just a few seconds. I have taken the car back to the audio shop 5 times and they keep giving me a different story. They first said I had a fuse problem and they fixed it, then they said the amp was getting too hot (Phoenix summer) and turned the gain down (didn't fix it), currently they are saying the stock wiring system or alternator cannot handle the load and that I need to purchase a supplementary battery to power the head unit and amp ($200 installed). I was not about to give more business to this shop and declined the supplementary battery.
I have had the battery/alternator checked by autozone and another auto shop and they say both are fine.
Has anybody had an experience like this??? Is the alternator or wiring simply too weak to handle a 200 watt head unit and a sincle 900 watt amp?? I am getting totally frustrated and don't know what to do. I have a feeling that the Lexus service dealer will blame the aftermarket additions, so I don't really want to take it to them.
Aside from this problem, I love the car!
Help!

 

First off, welcome to CL, fellow Arizonan who is most likely enjoying the imminent cool down.

Second, I highly doubt the shop knows what the problem actually is, and is band aiding it. Your deck is nowhere near 200 watts of actual power, nor is your amp pushing out 900 watts of continuous power, both of which are important to understand. The gain should have little/nothing to do with it heating up. It is not an output control, but many inexperienced installers (or those who choose not to learn) will use it incorrectly like that.

I would recommend that you speak with the manager of the shop and assure him that the car didn't have these problems before, and it shouldn't have these problems now. Your system is drawing approximately 38-43 amps, which is a very reasonable load for your alternator, even at idle. It sounds as though the power lead may be insufficient, but that's speculation as you didn't give much detail as to this portion of the system.

Give more info, get more help.

Big Mack

PS: if you don't want to divulge the name publicly, feel free to PM me as I'm curious to who did the work. I'm familiar with a lot of shops in the area.

 

Thanks for the quick reply and the welcome.
I have no problem divulging who did the work, it was Audio Express (Metro). I have been dealing with the manager, and he has been cordial, but has not fixed the problem.
I understand that the wattage in this system is not particularly high, but is still more than the stock system (stock system was not the Mark Levinson, or Bose or whatever the upgrade was in 2003).
As for power leads, they did use the stock wiring harness for the head unit. They wired a power lead (looks to be prerry heavy gauge) directly from the battery for the amp in the trunk.
At one point they told me it could possibly be the stock power line that needed replacing, but they have since moved on from that theory to trying to sell me the supplemental battery.
One of the auto shops I took it to said my alternator is fine and that I need to install a capacitor on the amp power line (they are not an audio shop though). So, it was when I suggested that to Audio Express they suggested the supplemental battery that they could wire to the head unit and the amp directly.
I have presented the problem to another audio shop (I just dropped into Best Buy and talked to an installer). What mystified that guy was that it was just the subs shutting down sometimes, but other times, and more often, the entire system shuts down. When it is just the subs shutting down, the light on the subwoofer control (from the head unit) goes from green (when operating) to red... So, I was told that since the whole system shuts down, a capacitor on the amp powerline will not help.
And, yeah it is finally starting to cool down here in PHX!!

 

Give more info, get more help. So far, we've gotten it narrowed down a bit, but I need to know what subs you have (model #'s and ohm), and if you know how it is wired. Can you see how large the gauge is on the wire to the battery? Did they upgrade the ground lead from the battery to the frame with the same (or larger) size? That's essential to know. It could be as simple as upgrading this, since power runs from negative to positive.

I'm thinking they wired it up in mono and the amp is shutting down when it goes below the load that it can handle, but I'm speculating.

As for needing a battery or a cap, let's worry about getting the system running correctly first. Your system DEFINITELY doesn't need an extra battery creating further load on the alternator.

Big Mack

 

He says when the system does shut down (either the subs or whole system) that it powers back up in a few seconds. To me, this seems like a voltage drop below 12v which would cause the sub amp or all the amps to shut down and then turn back on when the voltage stabilizes.

Here's a test to do, have the system on (car running) w/ no other accessories turned on (i.e. A/C. , blower, headlights, foglights etc.....). Is the system stable? Now turn on your headlights - what's the result? Turn on headlights and A/C - what's the result? How about pressing the brake pedal - result?

Could also be as simnple as the 12v remote wire being intermittment on the HU.

Let us know.....

 

I can almost guarantee that the altenator is going. What happens is the rectifier begins to go south and fails to allow charging of the battery while under load. The output of the stock Denso altenators is margianally adequate as it is. An aftermarket deck and amp can (not always) push an older or poor condition altenator to its breaking point.

My stock altenator on a 92 SC4 did this with only 1 five channel, 800 watt amp. Since I am a MECP certified installer I did all my own testing on the altenator when it was going out. NEVER did it show any problems on a load test. Issues only arose while driving.

Once the altenator was replaced all was perfect again.

Also, I would recommend an actual Denso factory replacement. I tried 2 aftermarket repalcement altenators and they would not work properly.

 

While it's possible it may be the alternator, I suspect it's more of a wiring issue. If it's an alternator issue, it can be as simple as unplugging the system and the problem should now be occurring with frequency even without the load because an alternator either works or it doesn't for the most part.

Brian, we still need more info to diagnose this beyond speculating.

Big Mack

 

I can't believe a shop would try to sell a HU as having 200 watts. That's a first for me!

This is why I do my own installs. I know everything and nothing

Good help from the guys above!

 

Isn't that the truth! Learn on your own and avoid the lying and cheating that goes on in an audio shop to earn a buck.

www.bcae1.com is an excellent beginner's route to learn the basics, then we can move on to more complex understandings from guys like www.zaphaudio.com, and DIYMA.

 

He never said the shop told him it was 200 watts, but I wouldn't put it past many shops. I think you have to keep in mind that many manufacturers now put "50 watts x 4" on their decks, so consumers are bound to believe it and not understand that it's WLS (When Lightning Srikes) power. When I was working in the field, I would never hype that because I knew it wasn't true. I'm all about giving the customer solid info as opposed to hype. Good audio isn't a mistake - it's a science!

I'm hoping the OP comes back so we can iron this out.

Big Mack

 

Couple things:

The alternator is probably not too weak...it is probably dying. However a simple volt meter will tell you what the truth is. I run a very powerful system compared with yours and my alternator is weaksauce compared with yours. Watts available to you have nothing to do with watts used, and be mindful that 900W is absolute peak and the useful RMS (think: musical average) is probably less than 1/2 of that, and that's only if you are CRANKING it. short answer: you aren't pushing your electrical system provided the system itself is working to spec.

The rest of your car will act very strange if it isn't receiving full voltage.

Assuming you test out the alternator and battery and they pass inspection, the next thing to look for would be your connections to those items including grounds. You can also check your voltage regulator to make sure it is keeping the right voltage coming out of the alternator.

When your 12v line drops to 10.5 or so, a lot of things get wonky and you are going to get the symptoms you've explained.

 

i need some help here. i was listening to my music td in my car. 3 jl audio w6's 10'' and a 1000 watt jl slash v2 amp and a raptor capicator. after i was driving bumping my beats i go over a bump and my subs stop working. what could this be my fuse isnt blown?

 

Wiring. check ur grounds.