battery drain issues
Thread Starter
Cruising
Joined: Aug 2016
Posts: 10
Likes: 3
From: Texas
battery drain issues
I've own a 78 vette in good shape (body and paint) just drop a new engine and it drove and feels amazing. i decided to send it to a shop to get rewired, because none of my gauges where lighting up. when i got the car back i got the transmission rebuilt and the car would drive amazing, but if i didn't drive the car for a day the battery would be completely drained. after that i got the alternator tested and a new battery and the alternator was good. i replaced all the fuses hoping that it will fix the issue but no luck. so decided to take the car out for a couple of meets, and i drove the car all day hoping that the battery wouldn't drain over night and surely it did 
. so i removed the side panels where the shifter sits and all the wires look new. any idea what the issues could be? any advice would be helpful
. so i removed the side panels where the shifter sits and all the wires look new. any idea what the issues could be? any advice would be helpful
Melting Slicks
Joined: Jul 2009
Posts: 2,091
Likes: 40
to drain over night , you got a pretty good leak going on for sure. Any of the alarm switches, light switches . I suppose that hated light contol box under the passenger dash might short itself internally . Dome delay whatever ...i hated that thing.
get an amp clamp see if you can find the guilty circuit.
you can take one fuse out to a circuit and see if that stops the drain , locate the circuit and then fix the issue.
amp meter is probably easier .
Radios are also know to have defects .
one issue with old cars is the column KEY switch .....they can wear and when you turn the car off ....the key actually can be pulled out with the electrical contact still on giving power to the circuit . When the key is pulled out , but power is still available to circuits . my keyswitch was worn so much on my Camaro , it released the key without the key in the full off postion. It was tricky to find this this.
get an amp clamp see if you can find the guilty circuit.
you can take one fuse out to a circuit and see if that stops the drain , locate the circuit and then fix the issue.
amp meter is probably easier .
Radios are also know to have defects .
one issue with old cars is the column KEY switch .....they can wear and when you turn the car off ....the key actually can be pulled out with the electrical contact still on giving power to the circuit . When the key is pulled out , but power is still available to circuits . my keyswitch was worn so much on my Camaro , it released the key without the key in the full off postion. It was tricky to find this this.
Last edited by LS4 PILOT; May 26, 2017 at 09:34 PM.
Racer
Joined: Jan 2005
Posts: 434
Likes: 47
From: Lake in the Hills IL
Check the courtesy timer as the above poster talks about. Follow the instructions for checking battery drain that include courtesy timer. You'll prob. find it pretty easy when searching. Just make sure the door is closed when you check so that the "timer" goes off after a min.
I went through everything like many here and that was my issue. I couldn't park anywhere for over a couple hours without disconnecting the neg. terminal...or risk being stuck there. I lived with it for over 10 years.
Once I determined that was my issue, $30 board replacement from Willcox fixed the issue in about 5 minutes or less. It's behind the glove box liner in an orange box. Wish I took care of it sooner, but probably the easiest C3 fix. I now can leave my car overnight, park, heck not drive it for a week or 2, and am all good. I probably have another small drain somewhere as it'll eventually drain... so I'll tackle that at some point.
I went through everything like many here and that was my issue. I couldn't park anywhere for over a couple hours without disconnecting the neg. terminal...or risk being stuck there. I lived with it for over 10 years.
Once I determined that was my issue, $30 board replacement from Willcox fixed the issue in about 5 minutes or less. It's behind the glove box liner in an orange box. Wish I took care of it sooner, but probably the easiest C3 fix. I now can leave my car overnight, park, heck not drive it for a week or 2, and am all good. I probably have another small drain somewhere as it'll eventually drain... so I'll tackle that at some point.
Le Mans Master
Joined: Aug 2006
Posts: 7,419
Likes: 1,555
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
At the starter, there is a BLACK wire that should be connected to a bell housing bolt.
It is a ground for the wiper motor and fan and might be connected to the top big lug on the solenoid by mistake.
If that is not the problem then see post 1 here.
https://www.corvetteforum.com/forums...with-pics.html
It is a ground for the wiper motor and fan and might be connected to the top big lug on the solenoid by mistake.
If that is not the problem then see post 1 here.
https://www.corvetteforum.com/forums...with-pics.html
Burning Brakes
Joined: Oct 2013
Posts: 992
Likes: 28
From: Sutton MA
You mentioned you just dropped a new engine in, A common mistake, one I did as well was when connecting the starter. There is a black ground wire that looks like it should fit on the positive terminal of the starter, but in fact it is supposed to ground out to the block and transmission. Check to see if somehow you connected it to the positive terminal ( the fat terminal ) on the starter, that will drain your battery over night. ask me how I know. ( Sorry while I was typing I didn't see the same info posted above )
Last edited by Tooonz; May 27, 2017 at 11:39 AM.
Melting Slicks
Joined: May 2015
Posts: 2,365
Likes: 428
From: Cape Girardeau Missouri
Titosvette:
I got notice of a reply from you saying that you'd already disconnected the alarm relay vut don't see it here now. ???
If you haven't found the problem already but before you begin the "remove all fuses--replace one-by-one checking for current draw with test light/ammeter thing" I suggest removing the CTSY fuse to see if it stops the problem. From the experience of my '79 and paying attention to this forum for a few years I am very confident in saying that is the most common-by far--circuit responsible for battery drainage.
I got notice of a reply from you saying that you'd already disconnected the alarm relay vut don't see it here now. ???
If you haven't found the problem already but before you begin the "remove all fuses--replace one-by-one checking for current draw with test light/ammeter thing" I suggest removing the CTSY fuse to see if it stops the problem. From the experience of my '79 and paying attention to this forum for a few years I am very confident in saying that is the most common-by far--circuit responsible for battery drainage.
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Le Mans Master
Joined: Aug 2006
Posts: 7,419
Likes: 1,555
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Good job troubleshooting!
The clock fuse also powers up the Courtesy Light Delay so that may be the problem.
Remove the orange CLD and connect the two WHITE wires together.
Your courtesy lights will now go ON and OFF as you open and close the doors lights.
Remove the orange CLD and connect the two WHITE wires together.
Your courtesy lights will now go ON and OFF as you open and close the doors lights.
Melting Slicks
Joined: May 2015
Posts: 2,365
Likes: 428
From: Cape Girardeau Missouri
Thread Starter
Cruising
Joined: Aug 2016
Posts: 10
Likes: 3
From: Texas
sorry i took so long to reply i was out of town, and yes i do. after i got back i notice that my dash lights don't turn on anymore and i know its cause i removed the fuse and I don't know much about electrical stuff when it comes to cars.