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04 Avy voltage flux, help needed

redheadedrod said:
Another consideration since your 105 amp alternator is not causing flickering...

What brand is your alternator. I have heard of some high output alternators putting out an excessively "noisy" output. Could be just a cheap alternator not putting out consistent output? If you have a 1farad capacitor you could check this by putting it at the battery from your alternator line and see if it smooths out the flickering... Would really be telling if you could put a scope on the output and see what it is doing.

Rodney
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It's Carquest. The data sheet said the ripple current was 38 amps. I don't exactly know what that means. I was actually thinking about putting a capacitor underhood today to help with the shock load of the fans. In more weird electrical issues, I replaced the interior lights with LED. I guess the BCM regulates voltage so turning the map light on is a partial voltage (dimmer) and turning them on from the dimmer switch or opening a door is full bright. But when I turned on both rear lights, then front lights, the rears would go out. Then turning off the fronts, the rears came on again. Same vice versa. It's like only 2 would go on at a time. All will come on if I open a door or use the dimmer switch. Odd.

So capacitor... I could hook to the battery, my 4ga amp cable downstream of the battery, the power distro block, or the fuseable link. If I want to smooth the power out for the entire car it would go alternator, cap, power distro block, right? It's been a hot minute since I one in.
 
I have a new lead. I found my carpet saturated with the midgate leak. It had been wet under there for awhile. Are there grounds and computer modules under the carpet? Water didn't make it into the console, but all the floors have wet padding. The more it's dried out, the more steady voltage has been.

It could be coincidence, but worth checking into.
 
They are not any grounds near the midgate.
 
Water intruded through the midgate and has saturated the padding all the way to the fire wall. Anything under seats?
 
Oh yeah, I didn't know you had that bad of a problem.

Try unplugging the seat and see what happens
 
Seat modules, wire splices, air bag module... All those are within range of a wet carpet.

So anything possible.

Rodney
 
Yay.....Should be fun ripping the interior out. On the plus side, I gatorbacked the bed and redid all the seals. 24 hours of rain and not a drop in the bed now.

 
So after years of chasing, which adds up to about 6 hours of troubleshooting, I found the main culprit was my painless fan controller. I ditched it for the Nelson Performance harness since I had BB activate my fans when they did my tune. Voltage stays steady, the ripple and flickering is greatly reduced if not gone.

My voltage still hangs out below 14V and readings from the battery and at the OBD2 port are both 14+. I?m betting it?s the other ground wire on the back of the block on the passenger side (G103 I think). By all my searching the cluster does ground through there. It seems like an indication problem because it also seems to affect the temp gauge.

When it?s cold, voltage will be at the 12 o?clock position on 14V and temp will be the same on 210. When it?s warm out, both needle will be at the 11:30 position.

Other than that, still plugging away.
 
Glad you finally found the problem, sometimes it's not what you think..

The other thing people forget about is the charge wire to the alternator, it's maybe an 8 gauge and should be upgraded to at least a 2 gauge and connected directly to the battery. You add power drawing accessories and as the alternator tries to keep up with the load it's doing it through that small charge wire and the battery acts as a buffer. It also has to be fused to match the higher output alternator.

I have a 225 amp Powermaster alternator with a 200 amp fuse. I've added dual electric fans, and about 1000 Watts of amps and have never had any electrical issues such as flickering or low voltage readings..
 
Aerohokie said:
All fixed, I replaced the positive cable too.
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There was another problem that I fixed simultaneously contributing to my voltage flux. The gauges were rebuilt at whitefacegauges about 4 years ago. Ends up, the power circuit on the board was going bad due to bad soldering. I had a local guy touch it up. I wanted to throw that out there for anyone having electrical issues also showing up in their gauges.
 
Aerohokie said:
All fixed, I replaced the positive cable too.
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First of all, thanks for documenting all this. I have a flicker/pulse that's existed since I bought my 2004 z71 used last October. Can you clarify that replacing the positive cable on the battery and that solved your flickering issue? My voltmeter on the dash will sometimes waver at low speeds or idle and cause pulsing in the cabin, dash, and headlights. However, alternator always tests fine, battery is only a year old and tests fine, and grounds seem to be in good shape. Thanks for any help you can give!
 
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