Odd battery drain problem on '68
Thread Starter
Instructor
Joined: Jul 2005
Posts: 220
Likes: 0
From: Oakdale Ca
Odd battery drain problem on '68
Helping a friend solve her battery drain problem on her '68, pretty much factory "as-is" car, 427, 4 speed Vert.
With all fuses pulled and the Alt disconnected, I still have a 3 amp draw when I pull the neg cable and measure between it and the Neg terminal on the battery.
Does anyone know of anything in this car that could draw power without being fused?
Thanks.
With all fuses pulled and the Alt disconnected, I still have a 3 amp draw when I pull the neg cable and measure between it and the Neg terminal on the battery.
Does anyone know of anything in this car that could draw power without being fused?
Thanks.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
If I had a DocRebuild wiring diagram I guarantee you I could find an answer quickly but I don't so working on memory check the wiper bypass **** under the steering column and see if it is on.
In the mean time I'll get into one of my crappy diagrams and see what else I can find. It almost has to be something that is fusible link protected.
In the mean time I'll get into one of my crappy diagrams and see what else I can find. It almost has to be something that is fusible link protected.
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
Check the condition of power lead from the battery. Do you have an additional power wire from the battery to the radio? Try to isolate each to determine if faulty wiring or some component still powered.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 220
Likes: 0
From: Oakdale Ca
There's no upgrades at all...well, there's an aftermarket radio, but I pulled the inline fuse on it.
I think i have it narrowed down, FWIW I have 4 ohms of resistance between the positeve cable and ground, so i reached in down by the starter and started tugging on the cables/wires and notice my meter started fluctuating, so I'm thinking either the wires are chaffed and scratching, or possibly the termilas on either the starter or the solenoid might be wiggling..causing the resistance to vary...I also did it while checking amps, and it seems to fluctuate form about a 3 amp draw, up and down to 2.5 to 4 amps.
I think i have it narrowed down, FWIW I have 4 ohms of resistance between the positeve cable and ground, so i reached in down by the starter and started tugging on the cables/wires and notice my meter started fluctuating, so I'm thinking either the wires are chaffed and scratching, or possibly the termilas on either the starter or the solenoid might be wiggling..causing the resistance to vary...I also did it while checking amps, and it seems to fluctuate form about a 3 amp draw, up and down to 2.5 to 4 amps.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
With that much draw, I would guess its the common 68 drain problem associated with the wiper motor and switch. If you cycle the wipers and let them park, I think you will find the drain gone. If you hit the wiper switch anytime after with the ignition switch off, it will return.
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 330
From: Indy Indiana
alternator diodes may be bad, disconnect your alternator and check for the same drain.. a 3 amp draw is pretty bad... if it was a short to ground somewhere, then you would more likely have something closer to a fire or bad smelly burned plastic..
also as suggested above, yes, check your wiper motor...
also as suggested above, yes, check your wiper motor...
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Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Thread Starter
Instructor
Joined: Jul 2005
Posts: 220
Likes: 0
From: Oakdale Ca
Thought I'd post an update/resolution.
We took the car into the shop, and here's what they did:
Found the 3.8 amp draw on the wiper motor to be the main culprit (as wombvette said), what stumps me on this is that there must be something non-fused (maybe through a fusable link?) that keeps power up to the wiper system, since I still had the draw with the fuses pulled out.
Another issue is was that the Alternator was replaced with one that had an internal regulator, seems who ever wired it in created some sort of "loop" while trying to bypass the external voltage regulator, this was causing a 1 amp or so draw.
Now here's the real cool part, the service man used to restore Vette's and happened to have a '68 Vette Alternator at his house, and basically gave it to the lady for free.
Total cost of the shop bill, including the Alt...
$315.00
Hat's off to Steve's Chevrolet in Oakdale, special thanks to Ken, the Service Department man.
We took the car into the shop, and here's what they did:
Found the 3.8 amp draw on the wiper motor to be the main culprit (as wombvette said), what stumps me on this is that there must be something non-fused (maybe through a fusable link?) that keeps power up to the wiper system, since I still had the draw with the fuses pulled out.
Another issue is was that the Alternator was replaced with one that had an internal regulator, seems who ever wired it in created some sort of "loop" while trying to bypass the external voltage regulator, this was causing a 1 amp or so draw.
Now here's the real cool part, the service man used to restore Vette's and happened to have a '68 Vette Alternator at his house, and basically gave it to the lady for free.
Total cost of the shop bill, including the Alt...
$315.00
Hat's off to Steve's Chevrolet in Oakdale, special thanks to Ken, the Service Department man.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Thought I'd post an update/resolution.
Found the 3.8 amp draw on the wiper motor to be the main culprit (as wombvette said), what stumps me on this is that there must be something non-fused (maybe through a fusable link?) that keeps power up to the wiper system, since I still had the draw with the fuses pulled out.
Found the 3.8 amp draw on the wiper motor to be the main culprit (as wombvette said), what stumps me on this is that there must be something non-fused (maybe through a fusable link?) that keeps power up to the wiper system, since I still had the draw with the fuses pulled out.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
You can also unplug the single red wire at the wiper motor and the 3 wire connector on the motor.
