1998 C5 not charging. Help?

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May 2, 2021 | 04:50 PM

DSSKing

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Joined: Jun 2003

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From: Markham Ontario

1998 C5 not charging. Help?

After I had my C5 tuned (procharged)> I drove it home with NO issues. As soon as I got to the garage, it went down to 10 volts
and the cluster said CHECK GAUGES. SO... Guessing it's the alternator......I have it on a 2 amp trickle but when I fired it up the
next morning, it was still reading below 12........

Suggesitons? I know alternators are like light bulbs and can go at any time...........

Thanks

May 2, 2021 | 05:29 PM

C5 Diag

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Joined: Sep 2013

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From: Cape Coral, Florida

Quote:

Originally Posted by DSSKing

I know nothing of tuning but maybe inquire from the tuner if he messed with anything. Are these voltage readings being read from the DIC or with a DVOM ??...with a DVOM I’d check the battery voltage after charging...12.66 volts is a fully charged battery...what does the voltage read during idle at the battery with the DVOM ??...how old is the battery ??...maybe would be a good idea to get it load tested...are you familiar with voltage drop testing of the charging system ??

Last edited by C5 Diag; May 2, 2021 at 05:36 PM.

May 2, 2021 | 06:55 PM

3sACROWD

Melting Slicks

Joined: Sep 2011

Posts: 2,258

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From: Appleton WI

I personally would start with getting the battery load tested. A bad cell can look like it is charged but the bottom drops out when a load is applied.

May 2, 2021 | 08:57 PM

mmartinez

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Joined: Sep 2008

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From: Espanola New Mexico

Load test battery, measure charging voltage at battery with a DVM, should be around 13.5-14.5volts depending on battery charge. It could also very well be your Ignition switch.

May 2, 2021 | 09:05 PM

MrNiceGuy!

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Joined: Aug 2017

Posts: 117

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From: Waterford New York

I'd try simple first. If the alternator tension pully and belt are not tight you drove home running the car off the battery. That might explain the battery being low.

May 3, 2021 | 08:09 PM

DSSKing

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Instructor

Joined: Jun 2003

Posts: 126

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From: Markham Ontario

Thanks guys. Turns out it was the alternator. The pulley had about an inch of play after I removed the belt. Ended up replacing the alternator
and that did the trick.

Cheers!!

May 4, 2021 | 12:52 AM

ncali

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Joined: Nov 2018

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now you need to go get your old alternator back because as you have probably already seen you now have charging issues. The alternator you put on will not work with the electronics in these cars

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