Mine did that and replaced the alt recently and it still does it. Even with new runs of wire for the Big 3.

 

charge back wire is the wire that runs from teh alt to the battery. No doubt it has corrosion in it. Replace it.

 

I honestly dont think that wire would be it...

I have a new (0awg) line running from the battery to alt. And the problem is still prevelent

 

What about the voltage regulator ?

 

the voltage regulator is built into the alt. i need to get it fixed, so i will try any good ideas. my positive cable allways has corrosion on it. i clean it every time i open the hood, so i will replace that wire.what size fuse should i put on it? i am planning on using 4awg. i dont know what else it could be. i allready replaced; battery, grounds, alt, belt, belt tensioner. after i replace the wire, i will let you know if it fixes the problem. thanks for all the help.

 

I would also check the voltage with a digital voltmeter right on the battery. See if it matches what your in-dash gage shows when the turn sihnal is blinking, lights applied, etc. If not, it could be one of the power input leads to the gage cluster is corroded or otherwise making poor contact.

 

My truck does the same exact thing, but honestly I think it's normal. When I first got the truck, I installed a sound system in it. Then, I decided to upgrade the alternator to a high output alternator. I bought it on ebay, and it left me stranded on the street. It was giving me signs when I first had it installed, but I had no clue. Everytime I would raise and lower my windows, the voltage needle would go down, and everything would dim. Now, let me mention that my voltage needle is not in the right spot, because when I had the custom gauges done, it wasn't placed right. I am going to fix it this coming week since I am installing digital gauges in a gauge pod. So after I had my truck towed to the mechanic, I bought a brand new alternator from Palladium at Advance Auto Parts, and had it installed. I have noticed that it does all of the things you described. And I have a lot of extra accessories running on the truck. But up to now, I really haven't had a problem with that alternator. I then decided to purchase a high output alternator at
Advance Auto Parts for almost $300. When I had it installed, along with a brand new Yellow Top Optima Battery, the voltage on the truck was reading very low(lower than with the Palladium) and the voltage would go down even further if I lowered the windows. So I then decided to reinstall the Palladium and keep that one. I still have the High Output one that I purchased at Advance Auto Parts. I also had it tested and it is perfectly fine. The only thing is that I have read that high output alternators have a low output at idle, which I believe is what I was experiencing. I still have it there, and might test it on the truck again. But to get back to your problem, I think it's normal.

 

i havent had a chance to change my wires yet, but maybe this week i will beable to. the problem is slowly getting worse. i will let you know when i change my wires. thanks for all the help.

 

well i finally got a chance to change my charge back wire, nothing. i think i am going to change my main cable that runs from my battery to my starter. i dont know what else to do. if it was a minor problem i could live with it, but some times my volts will drop so low that my truck will start to cut out. i allready replaced; battery, grounds, alt, belt, belt tensioner, and now charge back wire. if anybody can think of anything else, please let me know. thanks for the help.

 

its been a good minute since my last post, but just to update the post, the problem turned out to be my main power cable running from the alt to the junction block on the drivers side fender wall. i replaced it with 4awg cable and a inline fuse. thanks for all the help.