Need Help! Basshead problems or....?

[Karkov]

2007 Tahoe, 2 separate charging systems.

The headlights and dome lights (not dash) flicker when vehicle is running. Why? How do i remedy this? It never used to. When dark out it's annoying....

160 amp stock alt, XS Power D4800, otherwise all stock factory etc. for that charging system. The ONLY thing the two charging systems share/have in common is a belt (that is tight and close to new) and of course a common ground. I checked connections right at battery and they are tight and all seem good.

Suggestions?

[ShadeTreeMechanic]

Does it do it at all engine speeds or just idle? It might be the regulator. If the rectifier starts going out it would just lose output but I have never seen anything cause a flicker. Does your truck have that thing that the ground wire has to go through?

[Karkov]

Does it do it at all engine speeds or just idle? It might be the regulator. If the rectifier starts going out it would just lose output but I have never seen anything cause a flicker. Does your truck have that thing that the ground wire has to go through?

All engine RPM as far as I can tell. Driving down highway it still does it, warmed up or cold, it does it (does it worse when cold though). At times it gets better though and it's not real noticeable. Yes, I have the ground sensor loop. Everything for the factory electrical is still factory, except the XS Power battery. I put my battery maintainer on the stock battery over night a few times and didn't change anything. Voltage stays normal on factory side too.

So you think the stock alt has something wrong with it?

I should add, I do not have the battery temperature sensor like Dodge and Buick. Fuses are all good under hood. The connections seem tight on wires. stock alt. spins freely without belt on it like it's supposed to. I too am thinking the stock alt may be going out. It's about 10 years old (manufacture date) and had a stereo hooked to it briefly so it was beat on. Since it's 160 amps the vehicle must have a lot of electrical on it's own to draw too. I get off work 7 am and will remove it and get it tested at store and may replace it. Will have an update later in the day Friday.

[Skullz]

Check engine ground straps, might be corroding causing your problem.

Next will cost you, LED headlights or headlight relay kit or do both, another option are HID's.

[ShadeTreeMechanic]

Maybe you could put your spare alt in the stock location to test?

[Karkov]

Maybe you could put your spare alt in the stock location to test?

I recently sold my spare for the stock location. =(

However, I am gonna throw one positive run of 1/0 from under hood battery #1 to under hood battery #2 (separate charging systems) and if flickering stops as I stand there and lift it on and off the battery terminal maybe this might tell me it IS a charging problem? IDK......... I think it only flickers when running, which is when the alt. is spinning. Just turning lights on (vehicle off) they don't flicker. IDK, I can't wait to finish my shift and nip this problem in the butt ASAP. Thanks for the help, I will rule out Alternator very soon, haha

EDIT: Usually I would have the rectifier go out where the alt just stops charging but if either the regulator or brushes are going out then it does this? Or at least that's what i read online, I have no idea, lol..........

EDIT 2: Think I can sell it for more than I get for a core charge on here and have someone/company redo it and make it bigger/better? It's just a standard GM large case so only so much can be done but maybe it's worth something to someone who otherwise has trouble locating a spare alt?!

[ShadeTreeMechanic]

Connecting the two systems with the stock alt connected might not show a difference I don't know. I would almost take the connection off of the stock alt and tape it up. Then connect stock battery to big alt to test.

[Karkov]

Connecting the two systems with the stock alt connected might not show a difference I don't know. I would almost take the connection off of the stock alt and tape it up. Then connect stock battery to big alt to test.

I will do this too! Thanks, was thinking about this too....will test before and after remove wire from stock alt. Simple enough

[rocking.that.eclipse]

Don't you have an SMD volt meter? If you do you 'd be able to see the fluctuation in voltage. If your voltage in your whole car is dropping when the lights dim then i'd bet its something through all of them.

Since you have a stereo in it and it's only the lights that are doing it I'm willing to bet that it has something to do with grounds being loose.

Does it happen when you hit a bump or just when you are playing your stereo?

[Karkov]

Don't you have an SMD volt meter? If you do you 'd be able to see the fluctuation in voltage. If your voltage in your whole car is dropping when the lights dim then i'd bet its something through all of them.

Since you have a stereo in it and it's only the lights that are doing it I'm willing to bet that it has something to do with grounds being loose.

Does it happen when you hit a bump or just when you are playing your stereo?

I have a SMD volt meter on the stereo system. For the stock charging system I just use the dash voltage since it's pretty accurate and it doesn't bounce to the flickering. Grounds are tight, first thing I checked, haha. Since stereo is on it's own charging system it can be off and there is still a flicker, whether idling or driving down the highway at 3k RPM's. thanks though! =)

UPDATE: ran a 1/0 jumper from one battery to the other (charging system to charging system) started Tahoe, removed one end by hand over and over, flickering gets better but doesn't go away. Unhooked stock alt, WITH and WITHOUT jumper there is NO flickering. Whether the stock side is sitting there not getting charged OR at 14.9 volts (30 degrees out) there is NO flickering. Is the alt the common denominator?? I have the stock alt pulled out and ready to go to store, be back!!!!!!!