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Voltmeter drops to zero then comes back?

Posted: Thu Sep 21, 2023 7:52 pm
by crackerjacksle
2001 SLE, 95k miles, original alternator, 1.5 year old battery with clean tight connections, no check engine lights, no codes.

Started up as usual after sitting all day in 95° work parking lot, A/C & fan on of course.

After driving maybe two minutes the engine hesitated and faltered, dash lights dimmed and the voltmeter dropped to zero. The engine didn’t die and after maybe two seconds the voltmeter jumped back to normal around 14.
I turned off the A/C, fan & radio, put down the windows and continued home.

Five minutes later at higher speed it happened again; engine faltered, dash lights dimmed, voltmeter dropped to zero for two seconds then bounced back.

Made it home after another 20 minutes.

Car’s been sitting for a few days, started and idled a few times in the garage but hasn’t acted up.
I’ll drive the truck until I can diagnose and fix the Bonneville.

I’m wondering if the voltage regulator in the alternator is about to die? Any ideas?

Re: Voltmeter drops to zero then comes back?

Posted: Fri Sep 22, 2023 8:41 am
by 57j2olds
Sounds like alternator.

Re: Voltmeter drops to zero then comes back?

Posted: Sat Sep 23, 2023 12:32 pm
by crackerjacksle
installed a new alternator this morning. So far so good

Re: Voltmeter drops to zero then comes back?

Posted: Mon Sep 25, 2023 10:55 am
by Sirius
Thanks for the status update. Documenting a successful corrective action helps when others have similar issues.

Re: Voltmeter drops to zero then comes back?

Posted: Fri Sep 29, 2023 6:07 pm
by Captain Ali
crackerjacksle wrote:installed a new alternator this morning. So far so good

I have the same issue with my '02 Bonneville. After you installed a new alternator the problem was corrected 100% ?