I have a 1997 SSEi. I've posted on here a few times about this issue and I think I may have a better understanding of it but I have a question or two. I upgraded to an Optima Redtop and I've changed my alternator. Both test fine. I upgraded my cables to zero gauge wiring with copper ends soldered in. I did this because I have an aftermarket deck with aftermarket speakers and I used to have Two alpine type Xs with around 3000 watts going to them. I had a 50 farad capacitor as well to alleviate the strain on my alternator. But anyway. I've had this recurring issue where I'll be at a stop with my car in drive and the brakes applied and my lights dim. As soon as I give it gas they go back to normal. I've noticed it only when the headlights are on and the car is in drive and what not. I'm not sure if the idle changes with the lights off because of the drl. But again, I have had both my battery and alt checked separately and they both test fine. I'm thinking a ground issue and I was wondering if anyone might be able to tell me if there'* a reasonable amount of grounds in the car I could check or if I'm searching for a needle in a haystack.

you do have those amps or not anymore?

adding a sense wire is good for people with aftermarket stuff because it follows the load better. the stock alt has barley enough to power the stock load at idle, so if you didnt upgrade you didnt change anything. the battery really doent help because you are using the power from it faster than the stock alt can refill it. those monster alts are a gimmick sometimes because the poorly designed ones have the same idle output as stock so watch for that. the caps arent real necessary either. for a moderate system all you need is good wires and a good starting battery, but you need a bigger alt to refill the power the system takes

https://www.gmforum.com/electrical-1...rnator-278806/

Ok. I don't have the subs anymore. I have the deck still and the speakers but no amp. I bought the 240 amp alternator from a place called knukonceptz online but I changed it out because it didn't seem to make a difference. So a sense wire is a good idea? Where can I get one?

The sense wire mod can help.
I run an Odyssey battery & had quality power build a 110 amp at idle 160 amp max output. I had a bit of light dimming problems as well. I think my voltage dropped to about 11.5 at idle under loads stopped with brake lights etc on.
I left the stock wire in place which ran to the main under hood fuse block + then also ran a 4ga wire from the back of ALt directly to + on battery and that helped quite a bit.
The main problem is idle at anywhere from 500 to 600 rpm where the ALTs are tested at 800 rpm to produce the higher amp outputs.
Installing a bit smaller diameter pulley (which will spin faster) will get the amps up at idle the best. Did your 240 max amps output have at idle specs & did they down size the pulley at all?

See the link I posted for how to do the sense wire.

Like I said peak output is a useless spec but what everyone lists. Your engine sits at idle or near it all the time

It probably wasn't even 240, some shops tend to "upsell" products to just make a sale.


I agree with Justin and Art. Your current alternator may not be putting out enough at 650RPM but does fine at 800-1000+. This is a sure sign of a failing alternator.

If your grounding your stereo to the body it wouldn't be a bad idea to add a hefty ground to the body. the stock body ground is 16-12ga if I remember right.

In The Pk Ave the stock ground wire coming off the battery was small.
I cleaned up the stock wire & then added a more beefy ground to fender as well.

Things are greatly improved now.