Battery light

[RTW DC2R]

Lately on a few of my winter warm-up drives Ive noticed the battery light comes on periodically. It actually started last year after my rebuild but was very intermittent. I replaced battery and alternator as part of the rebuild so I'm fairly confident its a connector or bad/loose ground. Normally I wouldn't care too much but its been more prevalent during recent drives.

I do have an OBD2 scanner which shows voltage bouncing from 14v to 12v intermittently.

Aside from checking grounds and connectors, any other ideas?

[DC231]

Lately on a few of my winter warm-up drives Ive noticed the battery light comes on periodically. It actually started last year after my rebuild but was very intermittent. I replaced battery and alternator as part of the rebuild so I'm fairly confident its a connector or bad/loose ground. Normally I wouldn't care too much but its been more prevalent during recent drives.

I do have an OBD2 scanner which shows voltage bouncing from 14v to 12v intermittently.

Aside from checking grounds and connectors, any other ideas?

take the wire from the alt off and check the output at the post of the alt. if you still get the same readings then add a ground to alt and retest.. if it stays the same then its probably the voltage regulator in the alt... the voltage regulators are not "new" parts if you get a remanufactured alt so theres a chance it could be bad.. id pull the back plate off the alt and make sure all the little bolts are tight ive seen a voltage regulator ground back out once and caused a similar issue.. your alt should put out a steady 14+

[DC231]

if adding a ground to alt fixes it then you have a bad engine ground

[coolhandluke]

Excellent feedback.

[RTW DC2R]

Finally got the car back together and running so will troubleshoot the alt in the next few days.

Battery light is on even more now, voltage fluctuating all over the place from 14 to 11, even went to 9 at one point. Hooked a multimeter to the battery terminals and it was fluctuating there as well. It's bad enough that interior and exterior lighting flickers constantly.

What do you mean "add a ground to the alt"?

Side note, last year during a full rebuild I had to bang the shit out of the lower hinge bolt with a hammer to remove it from the bracket. Seems like the battery light has been an issue since then so maybe I shocked something loose.

Also ordered a Denso reman just in case.

[DC231]

Finally got the car back together and running so will troubleshoot the alt in the next few days.

Battery light is on even more now, voltage fluctuating all over the place from 14 to 11, even went to 9 at one point. Hooked a multimeter to the battery terminals and it was fluctuating there as well. It's bad enough that interior and exterior lighting flickers constantly.

What do you mean "add a ground to the alt"?

Side note, last year during a full rebuild I had to bang the shit out of the lower hinge bolt with a hammer to remove it from the bracket. Seems like the battery light has been an issue since then so maybe I shocked something loose.

Also ordered a Denso reman just in case.

just add an extra ground directly to the alternator case to see if it helps.. if your engine grounds arent up to par then this will let you know.. im betting that the voltage regulator has taken a crap...

were you able to check the voltage at the alternator post? if you get proper voltage at the post then your alt wire that runs to the fuse panel is probably burned up or corroded. if you dont get proper voltage at the post then either the voltage regulator is bad or your alternator needs to be rebuilt.. im guessing the voltage regulator because you said its a reman alt.. as i said before when you buy a reman alternator its only been rebuilt with new bearings and brushes, the voltage regulator would have never been replaced if it worked fine when they did the re-manufacturing process..

please at least check the voltage at the post if you can before swapping the alt out or you may end up putting the new alt in to get the same results...

[RTW DC2R]

Thanks for the feedback.

So by adding a ground, you mean simply adding a wire to the alt and ground it on the chassis or something and see if the problem persists?

I misspoke when I said I replaced the alternator. This is the original alternator that I beat the crap out of with a hammer. I replaced so much shit on the car I cant keep track

Hope to troubleshoot this tonight. I have a Helms too but the pages for troubleshooting the charging system give me a headache

[DC231]

Thanks for the feedback.

So by adding a ground, you mean simply adding a wire to the alt and ground it on the chassis or something and see if the problem persists?

I misspoke when I said I replaced the alternator. This is the original alternator that I beat the crap out of with a hammer. I replaced so much shit on the car I cant keep track

Hope to troubleshoot this tonight. I have a Helms too but the pages for troubleshooting the charging system give me a headache

correct.. add wire to alternator then ground to chassis.. you can ground right to the upper alternator tensioner bolt for quick testing..

ok so the alt is original and never been repaired..

first i would still try to test the voltage at the post of the alternator for reassurance that its not faulty wiring.. if you get low voltage at the post still then the alternator is most likely in need of rebuild..

you can check locally for a repair shop and find great deals.. here in jacksonville fl i take my alternators and starters to a place called Peavey Bros and they have never charged me more than $70 to rebuild anything..

[DC231]

tip for removal and installation---you can loosen the 2 master cylinder bolts from the booster and gently move the master cylinder out of the way or if i remember correctly you should be able to remove the 3 intermediate shaft bolts and you can pull the shaft out of the trans just enough to get the alternator out/in.

[aklackner]

When I installed the motor in the LS I don't know if I did the alternator before or after the halfshaft. I do see the service manual calls out removing the entire brackets so that may provide enough wiggle room to get it out?
I remember the rack replacement looking like it would a big challenge with the motor and everything in but following the service manual it did work out as the process was written, it just took patience.