What keeps killing my Vette?
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Joined: Apr 2015
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What keeps killing my Vette?
1999 Vert. A few weeks ago went out for a ride and the car was dead. Jumped it and took it to Autozone to have it checked. Battery was good and acutually had a Jan 2015 battery (got the car in March). No other problems.
Two weeks ago dead again.. I had left the hood up while working on a few things and thought that was the problem. Did not drive yesterday but started the car and all was fine.
Went to pull it out today to put air in the tires and totally dead. Seems to be dying while sitting.
Ideas?
Thanks
Two weeks ago dead again.. I had left the hood up while working on a few things and thought that was the problem. Did not drive yesterday but started the car and all was fine.
Went to pull it out today to put air in the tires and totally dead. Seems to be dying while sitting.
Ideas?
Thanks
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
Make sure all lights are going off. Under hood, glove compartment etc. If you have an aftermarket amp make sure that isn't on. If you have a voltmeter, unhook a battery cable and see if there is a drain. A C5 should go more than three weeks before battery is dead. Gauge show battery charging? It should show over 13V.
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
Maybe it's never reached full charge.
Melting Slicks
Joined: Oct 2005
Posts: 2,989
Likes: 352
From: Carson City Nevada
I don't know how reliable these auto store testers are. My buddy just replaced his bad battery with a another (good) one, even though the local parts store tested it (the bad one) and said it was good. It wasn't. I think it sounds like you have a faulty battery
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
Paracitic current drains are common problems on the C5. Here is some info about current draw in the C5 by Bill Curlee, Forums resident Electrical Wizard:
The correct BCM current draw should be 20 Milliamps or less. Most C5 run around 25ma
but I have see some as low as 15 ma.
Leave the engine compartment fuse box for last and start with the passengers compartment
box first. Pull the power seat breakers FIRST! The power seats have a tendancy stay on
and cause this issue.
Also pull the fuses for the Bose system amp.
Examine the car in the dark for lights staying ON.
Once you prove the interior circuits good,,, check the headlight circuits, and then test
the current draw of the alternator.
Look at my electrical stickey. I think I cover this in detail in that post.
There are several COMMON things that cause excessive current draw
-Seat multifunction switch & Lumbar Switch
- Bose Amp relay stuck on
- Alternator didoes bad and drawing current
- Headlight control module bad
- Interior light on (check in the dark)
- Added aftermarket accessory not shutting off
And a thread by him with directions and pictures on isolating the cause:
http://forums.corvetteforum.com/1567522286-post590.html
Using a battery tender only works if the drain is less than the charge current of the tender. Most tenders are about 1.25 amps.
The correct BCM current draw should be 20 Milliamps or less. Most C5 run around 25ma
but I have see some as low as 15 ma.
Leave the engine compartment fuse box for last and start with the passengers compartment
box first. Pull the power seat breakers FIRST! The power seats have a tendancy stay on
and cause this issue.
Also pull the fuses for the Bose system amp.
Examine the car in the dark for lights staying ON.
Once you prove the interior circuits good,,, check the headlight circuits, and then test
the current draw of the alternator.
Look at my electrical stickey. I think I cover this in detail in that post.
There are several COMMON things that cause excessive current draw
-Seat multifunction switch & Lumbar Switch
- Bose Amp relay stuck on
- Alternator didoes bad and drawing current
- Headlight control module bad
- Interior light on (check in the dark)
- Added aftermarket accessory not shutting off
And a thread by him with directions and pictures on isolating the cause:
http://forums.corvetteforum.com/1567522286-post590.html
Using a battery tender only works if the drain is less than the charge current of the tender. Most tenders are about 1.25 amps.
but make sure you have a fully charged battery first.
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Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
When the key is in ON with the engine not running, the voltmeter on the dash shows the voltage output of the battery. When the engine is running it shows voltage output of the charging system.
Key on, not running should show almost 13 volts. Almost 14 volts when running. Does it?
Key on, not running should show almost 13 volts. Almost 14 volts when running. Does it?
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
Not accurate on 2 counts. First the gauges on the C5 are down stream of the ignition switch and it is a well known fact that most if not all C5 ignition switches suffer from carbon build up as well as pitting of the switches contact surfaces that result is voltage drop across the contacts. Second with the key in the ON position and engine off there are many electrical circuits in the C5 that are loading the battery.
So what you see on the gauges with the key ON and engine OFF will be a lower number than if you put a digital multi meter across the battery posts.
So what you see on the gauges with the key ON and engine OFF will be a lower number than if you put a digital multi meter across the battery posts.
Key on, not running battery output.
Running.... alternator output. Might not be exact, but it's probably close.
Last edited by JR-01; Jun 22, 2015 at 09:26 PM.
Le Mans Master
Joined: Sep 2013
Posts: 8,900
Likes: 1,074
From: Wisconsin
Wouldn't be the first time the Owners Manual or the Shop Manual were not accurate.
As for how far off it is, do the measurements some time. On my own car the dash shows 12.3 volts with Key ON and engine OFF. But the voltage across the battery posts measures 12.93 with a Digital Multi Meter.
As for how far off it is, do the measurements some time. On my own car the dash shows 12.3 volts with Key ON and engine OFF. But the voltage across the battery posts measures 12.93 with a Digital Multi Meter.