Battery Drain (Part 3)
Thread Starter
Drifting
Joined: Mar 1999
Posts: 1,381
Likes: 15
From: Lusby MD
Battery Drain (Part 3)
OK. My turn to post.
I saw the previous 2 message strings on this topic and I followed redvetteman's very well thought out approiach of tracking where the current drain is coming from. I broke out my 12V test light, disconnected the positive terminal of the battery, and put the test light between the positive cable and the positive terminal. I got a bright light. Ah ha!
Then I disconnected the alternator. Then I one by one removed the fuses (leaving them out as I went). The test light never went out. Now I have a car with a disconnected alternator and no fuses, but still have a drain.
Just a note here - all the wiring harnesses in this car have been replaced during the restoration so there shouldn't be any whacky bubba-ized shorts. I seem to remember a battery draw problem before I started though (I never drove the car when I bought it - it was pretty much a basket case). I recognize that there could well be some missing grounds - particularly under the dash, but I don't know. The switches (headlight switch ect) were, for the most part retained.
Any advice?
I saw the previous 2 message strings on this topic and I followed redvetteman's very well thought out approiach of tracking where the current drain is coming from. I broke out my 12V test light, disconnected the positive terminal of the battery, and put the test light between the positive cable and the positive terminal. I got a bright light. Ah ha!
Then I disconnected the alternator. Then I one by one removed the fuses (leaving them out as I went). The test light never went out. Now I have a car with a disconnected alternator and no fuses, but still have a drain.
Just a note here - all the wiring harnesses in this car have been replaced during the restoration so there shouldn't be any whacky bubba-ized shorts. I seem to remember a battery draw problem before I started though (I never drove the car when I bought it - it was pretty much a basket case). I recognize that there could well be some missing grounds - particularly under the dash, but I don't know. The switches (headlight switch ect) were, for the most part retained.
Any advice?
Racer
Joined: Nov 2000
Posts: 440
Likes: 0
From: Corvallis OR
Re: Battery Drain (69L71)
Try disconnecting the fusable links at the starter?
Ck the hood light
Theres wiring diagrams at http://www.corvettefaq.com for a 78, that might be helpful
Jim-K
Ck the hood light
Theres wiring diagrams at http://www.corvettefaq.com for a 78, that might be helpful
Jim-K
Le Mans Master
Joined: Jan 2001
Posts: 9,247
Likes: 221
From: Dryden MI
Re: Battery Drain (69L71)
Check the battery cable. I think it goes right to the starter, disconnect it there. If light is still on it is probably the cable insulation worn out enough to go to ground, without causing a dead short. Also If that is not the problem install your two fusible links one at a time to the starter post and check for short. Let us know what you find. Roger
Thread Starter
Drifting
Joined: Mar 1999
Posts: 1,381
Likes: 15
From: Lusby MD
Re: Battery Drain
OK.
I unplugged all the wired to the wiper motor - light stays on
I removed the main battery cable. - light went out so there's no short in the main feed, and then reconnected it.
I removed the 2 secondary starter wires (yellow and purple so I bypass the fusable links compleely) - light stays on
I removed the other red wire on the main starter lug (the one that feeds power to the whole car) - light goes off.
So....
I don't have a problem anywhere in the fused circuits, the wiper circuit, or the starter circuit. It's got to be downstream of the starter. This isn't a shock because when I connect the battery I get a click from the horn/buzzer relay. I replaced that relay with another one I had laying around but it hasn't changed a thing.
Help!
I unplugged all the wired to the wiper motor - light stays on
I removed the main battery cable. - light went out so there's no short in the main feed, and then reconnected it.
I removed the 2 secondary starter wires (yellow and purple so I bypass the fusable links compleely) - light stays on
I removed the other red wire on the main starter lug (the one that feeds power to the whole car) - light goes off.
So....
I don't have a problem anywhere in the fused circuits, the wiper circuit, or the starter circuit. It's got to be downstream of the starter. This isn't a shock because when I connect the battery I get a click from the horn/buzzer relay. I replaced that relay with another one I had laying around but it hasn't changed a thing.
Help!
Thread Starter
Drifting
Joined: Mar 1999
Posts: 1,381
Likes: 15
From: Lusby MD
Re: Battery Drain (69L71)
OK!!!!!!
Traced the problem to the horn contact circuit! Now I at least have someplace to look for a fix. The column isn't all the way back together so it could be that the horn contacts aren't hooked up. I'm not sure yet how I'll approach that. But for now I can pull the plug on the horn relay and be good to go!
Now I have to figure out why my parking lights go on when I hit the brakes....
Traced the problem to the horn contact circuit! Now I at least have someplace to look for a fix. The column isn't all the way back together so it could be that the horn contacts aren't hooked up. I'm not sure yet how I'll approach that. But for now I can pull the plug on the horn relay and be good to go!
Now I have to figure out why my parking lights go on when I hit the brakes....
