This one's got me confused, mainly cuz its so hard to see.

i guess to start off, i should say that the truck runs fine but every once in a while it does its little ding thing, the check guages light comes on and the voltage display for the battery drops to the very left....i figured maybe it was just the guage acting up but when i measured the battery i only had 11.47V on it which means it wasn't charging. i went to auto zone, the battery test came out fine, the alternator test came out fine too...i tried following the cables from teh alternator but they just bury in the engine...

It also doesn't always do this, every once in a while it does it and then ten minutes later the light goes off, the guage goes up and the battery voltage goes up to 13.7V again... i don't get it...

 

Seems to me it may be a short somewhere. Posibly a wirejacket has exposed some wires and now they're arcing somewhere. Try setting up a gage or have someone sit in the cab with it running and wiggle (gently) various wires under the hood. If you see a drop in volts the wire your wiggling is most likely the problem. A good place to look for worn out wires is along places where it enters the cab or anywhere a wire could rub. Also look for non functioning electrical items or dim lights those are sure signs of a bad wire in that circuit. Also check your fuses.

 

defintaly look for a shoert in the charging circuit, an doulble check that plug on the top of the alternator. I was working on my truck an accidentally unplugged it. all those lights an the batt wont charge if something happened to the plug or the wires. follow those wires there easy. jus take some of the black pretective tubing off to check for rubbing.

 

Alright, i did what y'all said followed every wire but nothing...still the exact same problem...

 

Well, then your truck just hates you.

No, I'm kidding. It sounds stupid, but did you try checking and cleaning the battery terminals?

 

I've had alternators begin to go bad and do the exact same thing you are describing, in my Jeep I couldn't figure it out, the alternator tested good, but I figured because I already had it removed from the truck, that I might as well replace it, and what do you know it fixed the problem. What I would do is buy a new alternator, but don't turn in your core unless it fixes the problem, if it doesn't then you have an extra alternator for your truck.

 

The tiny plug in the back of the alternator controls the gauge pod in the cluster. If you unplug it, the voltmeter needle will not move and you will get an instant CEL. My guess is the plug is loose or you have a short somewhere in that plug's wiring.

Other possiblilities are a charging system relay shorting, or the IOD fuse could be loose.

Are you running any HD power drawing devices like electric fans or big stereo system with amps?

 

yeah i've got a stereo two amps, a tv kc lights, winch, HID headlights, etc.

 

you may need a larger alt maybe even run that sytem on another battery it sounds like the fuse between the alt and the battery for one and the other sounds like u got to much drawing on yer batt so i would suggest getting a larger alt or like i said another battery specifically for ur sound system...my 0.02 cents...j