68 battery short
Thread Starter
Instructor
Joined: Nov 2019
Posts: 245
Likes: 15
68 battery short
Put a new battery in the car and within 3 days it was dead. Battery was discharged to less than 7 volts. I know I didn’t leave anything on to cause the problem and expect I have a short somewhere in the system. I’ll start troubleshooting the problem tomorrow but thought I would query the group for any historic sources of a ground.
Any suggestions?
Any suggestions?
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Amp meter between Batt Neg post and the cable. Should be quite a draw right now.
Start pulling fuses until zero or almost zero on the meter.
A clock, alarm system or stereo may have some draw.
And in rare cases, a light in the rear compart. Or a light at the spare tire carrier.
Some early C3s had issues with wiper relay drawing on a fully charged battery? IDK
Start pulling fuses until zero or almost zero on the meter.
A clock, alarm system or stereo may have some draw.
And in rare cases, a light in the rear compart. Or a light at the spare tire carrier.
Some early C3s had issues with wiper relay drawing on a fully charged battery? IDK
Burning Brakes
Joined: Dec 2017
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2023 C3 of the Year Finalist - Modified
I had a fault/short in the voltage regulator circuit on the alternator that was draining the battery. Easy to check, just unplug the connection on the alternator and using an ammeter on the battery, see if the current draw goes away.
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
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2016 C3 of Year Finalist
the voltage regulator/ horn relay and wiper override are the 3 big ones.The light in the glove box can kill your battery pretty quick. Fully charge the battery and disconnect the positive cable. Hook a meter on the positive post and to the positive cable. Turn the meter to amps and see if there is an amp reading. if there is then disconnect fuses until the amp draw drops.
Le Mans Master
Joined: Jan 2001
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Batesgar
Before you go off half-cocked just ensure that your wipers did not get interrupted mid cycle. That will maintained the wiper solenoid energized and kill your battery. Let me see if I can find the post describing it.... but essentially once you start a wiper cycle you have to let them complete, otherwise if you interrupt it, then the wipers will "re park" but the solenoid will remain energized.
There may be nothing wrong but Operator error. (well, and not the best design)
Before you go off half-cocked just ensure that your wipers did not get interrupted mid cycle. That will maintained the wiper solenoid energized and kill your battery. Let me see if I can find the post describing it.... but essentially once you start a wiper cycle you have to let them complete, otherwise if you interrupt it, then the wipers will "re park" but the solenoid will remain energized.
There may be nothing wrong but Operator error. (well, and not the best design)
Last edited by carriljc; Oct 23, 2021 at 10:43 PM.
Le Mans Master
Joined: Jan 2001
Posts: 6,742
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Batesgar
Here you go: https://www.corvetteforum.com/forums...post1601496240
And some more info:
https://www.corvetteforum.com/forums...post1594776228
Here you go: https://www.corvetteforum.com/forums...post1601496240
And some more info:
https://www.corvetteforum.com/forums...post1594776228
Last edited by carriljc; Oct 23, 2021 at 10:46 PM.
Thread Starter
Instructor
Joined: Nov 2019
Posts: 245
Likes: 15
Thanks for the reply’s and related threads. The wiper override is a good one. I was working on the windshield wiper pump the day before the battery went dead. When I replaced the battery I did hear wiper sounds that might relate to the wipers being energized and causing the battery drain.
I’ll check power draw at the battery tomorrow and if I see acceptable levels will conclude it was the wipers being left energized.
I really appreciate the forum, it’s loaded with experts and always my best source for advice.
I’ll check power draw at the battery tomorrow and if I see acceptable levels will conclude it was the wipers being left energized.
I really appreciate the forum, it’s loaded with experts and always my best source for advice.
Le Mans Master
Joined: Jan 2001
Posts: 6,742
Likes: 1,384
Don't make any changes to being with.
You're going to need a good battery to start.
Don't even have to turn the key to ON.
Hook it up and see if you hear a solenoid pick up -- listen for sound behind dash in the tach area. (If you have someone help, then put your paw on it before hooking up the battery--that way you can "feel" and "hear" it pick up).
Take an initial amp draw reading.
Let the wipers cycle through and park ( don't interrupt them).
Take another amp-draw reading...... if this was the problem it should drop dramatically.
You're going to need a good battery to start.
Don't even have to turn the key to ON.
Hook it up and see if you hear a solenoid pick up -- listen for sound behind dash in the tach area. (If you have someone help, then put your paw on it before hooking up the battery--that way you can "feel" and "hear" it pick up).
Take an initial amp draw reading.
Let the wipers cycle through and park ( don't interrupt them).
Take another amp-draw reading...... if this was the problem it should drop dramatically.
Thanks for the reply’s and related threads. The wiper override is a good one. I was working on the windshield wiper pump the day before the battery went dead. When I replaced the battery I did hear wiper sounds that might relate to the wipers being energized and causing the battery drain.
I’ll check power draw at the battery tomorrow and if I see acceptable levels will conclude it was the wipers being left energized.
I really appreciate the forum, it’s loaded with experts and always my best source for advice.
I’ll check power draw at the battery tomorrow and if I see acceptable levels will conclude it was the wipers being left energized.
I really appreciate the forum, it’s loaded with experts and always my best source for advice.
Last edited by carriljc; Oct 25, 2021 at 09:46 PM.
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Thread Starter
Instructor
Joined: Nov 2019
Posts: 245
Likes: 15
Thanks again for some steps to troubleshoot.
As I stated, when I put a good battery in place I heard a dash wiper noise suggesting I might have left the wipers energized killing the original battery. I’ll known more today when I do some amp readings at the battery.
As I stated, when I put a good battery in place I heard a dash wiper noise suggesting I might have left the wipers energized killing the original battery. I’ll known more today when I do some amp readings at the battery.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,212
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
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that would be the wiper override I mentioned
Thread Starter
Instructor
Joined: Nov 2019
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Likes: 15
That wiper system is pretty complex due to its mechanical, electrical and vacuum systems. I’m just glad for now mine are working properly (short of the washer fluid pump). In simple terms, what does the override involve, what does the solenoid trigger and what makes the noise you hear in the dash?
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,212
Likes: 9,350
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
The 68 is ground activated so your wiper switch is changing grounds to different parts of the motor. So the quick and easy explaination that answers most of your questions is.....Theres a relay under the center console that is controling master power to the motor, the solenoid on the tach controls vacuum to the vacuum relay down in your passenger front fender, just above your fluid reservoir, that could be clicking The park relay is internal to the motor and on seperate system. That park relay is controled by the wiper switch but when you want to work on your wiper blades you cant just shut off the motor and stop the sweep. It has direct power and controls the other power relay so until the wipers park there is power to the motor....That isnt totally accurate but it is good enough for this explanation. When you rotate the wiper override it cuts the ground so the motor stops during the park phase but the relay still has power because the park switch hasnt closed. Thus if it is bumped even while parked it can leave a current draw
So when you turn on your car you maybe hearing that relay clicking off then on again.
Theres a better explaination on an AIM addendum but i dont have it on my phone. Just know that a toggle switch in place of that rotary switch will save you lots of dead batteried
So when you turn on your car you maybe hearing that relay clicking off then on again.
Theres a better explaination on an AIM addendum but i dont have it on my phone. Just know that a toggle switch in place of that rotary switch will save you lots of dead batteried
Last edited by Rescue Rogers; Oct 24, 2021 at 12:13 PM.
Thread Starter
Instructor
Joined: Nov 2019
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Complex….but I think I understand. Was wondering why that wiper switch under the dash was rotary versus a toggle.
I assume if that rotary switch isn’t turned completely off you have a battery drain?
I assume if that rotary switch isn’t turned completely off you have a battery drain?
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,212
Likes: 9,350
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Mine was so sensitive that it seemed just one or two degrees of rotation would enable it. I bumped mine with my leg all the time. I have a battery disconnect that I engage whenever I shut off the key and the I finally just put in a toggle this summer
Burning Brakes
Joined: Jul 2018
Posts: 979
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From: Maryland
Looks like you have the problem fixed, but if you ever get a battery drain again..
If I suspect a short somewhere I normally unhook the positive and negative connections to the battery and use the Ohm selection of your VOM to across the (unhooked) battery leads. Use Ohms law for help in this, i.e. 12V / Ohm reading = current being drawn.
If I suspect a short somewhere I normally unhook the positive and negative connections to the battery and use the Ohm selection of your VOM to across the (unhooked) battery leads. Use Ohms law for help in this, i.e. 12V / Ohm reading = current being drawn.
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Following up (I apparently hit Reply too early) by removing the battery leads you reduce the chance of damage to your battery and even to your VOM in Amps setting as some Amp selections max out
at 10 amps and a short can easily pull more and damage the VOM and possibly you if you are holding it.
at 10 amps and a short can easily pull more and damage the VOM and possibly you if you are holding it.
Thread Starter
Instructor
Joined: Nov 2019
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Luckily the battery that the car drove down to under 7 volts recovered when removed as was able to hold a charge. I put it back in the car and connected my meter between the neg terminal and the lead and saw no drain when set at 10 amps. I ran the wipers and confirmed the over ride **** was turned completely off and turned the wipers off to fully cycle and again the battery showed no drain. I’ll try checking ohms between the pos/neg leads with the battery disconnected but expect to see little to no drain.
I have to conclude I left the wipers in the mid cycle when I was working on the wiper washer and that caused the battery drain.
I have to conclude I left the wipers in the mid cycle when I was working on the wiper washer and that caused the battery drain.