charging light and problems

[Doug Kaye]

this is driving me crazy..
Last year the battery went bad, (I think) causing the charge light to flicker at random times. Multimeter confirmed wildly fluctuating voltage when the light was flickering. Usually a bad battery will show up as dim lights, hard starts etc, but this one started fine right up until it failed completely in a Nebraska thunderstorm. Replaced the battery in the thunderstorm, a real joy, and everything was fine until a month ago.

This time the charge light goes on dimly, rather than flickering. Checking showed a steady 12v with the engine running, not a changing voltage. This looked like a bad alternator/voltage regulator to me, replaced the alternator under warranty.
Now the random flickering and changing voltages is happening again. There's no pattern I can find - revving the engine doesn't change, slowing or speeding up doesn't change, stopping and restarting doesn't change. It starts on its own randomly and stops the same way.

Battery is not yet a year old, new alternator, serpentine belt replaced last year at the first go-round of weird flickerings.
The alternator is a remanufactured one so I have some doubts about it.

Checked all the ground cables, replaced the ones under the driver/passenger doors some years ago, cables from battery look sound, hood strap is good.

Anyone have any ideas ? I may have to go to the dealer, these electrical things are a bear..

 

[dvdswan]

Checking the grounds... Did you physically disconnect them and inspect for corrosion on the matting surface and inspect the ends of the cables for corrosion underneath the insulation?

 

[Doug Kaye]

thanks - yep, disconnected and took the cables off to have a good look.. no visible problems.
had exactly that problem with my old Sienna and cable replacement fixed it there.
I'd replace these except it seems these cables are no longer made and would have to jury-rig something..

 

[dvdswan]

Rockauto shows direct replacements for mine...

https://www.rockauto.com/en/catalog...4.0l+v6,1385355,electrical,battery+cable,2500

 

[Nick Mann]

Did you check for codes?
Did you do a ripple test for clean DC voltage output?
Try running a jumper wire from the battery negative too the alternator housing. See if the flickering goes away.

 

[Doug Kaye]

thanks for suggestions..

cable links - unfortunately my cables don't look like that, instead they vanish into a giant sausage of other wires wrapped together, which then dives deep into the engine. The ends look clean but not sure about the middles in that sausage..

no codes oddly, would have expected something but no.
not sure what a ripple test is, will google..

tried that jumper wire, from battery to frame ground, and from battery to alternator, did not affect.

haven't seen the flickering in a week now, but I don't trust it a bit.

 

[Todd Z]

Change the serp tensioner and run the 1/2" shorter belt to eliminate all that. a weak battery can cause issues, ALSO starting a truck with a dead battery WILL damage the alternator if you use it ti recharge the battery.. its NOT a charger, it s a maintainer...

 

[Doug Kaye]

drove it out to Pumphouse on the CO river, went through some rain and the flickering began.
Turned off onto dirt and hit a few good bumps, fixed it. Another bump knocked it out again. Deliberately accelerated onto some washboard and that fixed it again ;-)
It went into and out of flickering for about 10min on a good tar road on the way home.
Bad wire or bad connection seems the most likely to me.. going to try adding new cables, one to bypass existing connection to battery, another entirely new cable to ground from alternator mounting bolt.

camping was good as always..