Topic: Electrical and Battery dead
in Forum: C3 Electrical
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New components - starter, battery, generator/alternator unit. After sitting for 7-10 days, dead battery but can charge up with jump. Question is.. Is it worth replacing two main wiring cables ground (about 21" long) and the other that runs to (?) starter about 60" runs from battery to engine area. Other ideas? 

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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
I doubt if changing those cables will cure your problem, but if they look old, it wouldn't hurt anything to do so.
You have an open circuit somewhere. I had a similar problem with my '78. My problem was the timer for the interior courtesy lights had gone bad and would either not turn off the lights or randomly turn them on and would run the battery down. If you have a courtesy light delay feature, check it out.
If that's not the problem, here's the "poor man's method": make sure the battery is disconnected and completely charged and take a voltage reading. Hook the battery back up and check the voltage again and see if there's a drop in the voltage reading. If so, one at a time, remove each fuse from the fuse box and check and see if the voltage stays the same or goes back up to normal. If the voltage goes back up, you've identified the circuit your voltage drain is coming from. Then you can check further and find out exactly which accessory is causing your problem.
Hope you find your problem quick.
You have an open circuit somewhere. I had a similar problem with my '78. My problem was the timer for the interior courtesy lights had gone bad and would either not turn off the lights or randomly turn them on and would run the battery down. If you have a courtesy light delay feature, check it out.
If that's not the problem, here's the "poor man's method": make sure the battery is disconnected and completely charged and take a voltage reading. Hook the battery back up and check the voltage again and see if there's a drop in the voltage reading. If so, one at a time, remove each fuse from the fuse box and check and see if the voltage stays the same or goes back up to normal. If the voltage goes back up, you've identified the circuit your voltage drain is coming from. Then you can check further and find out exactly which accessory is causing your problem.
Hope you find your problem quick.
Don't forget the wiper over-ride switch at the bottom of the dash (above your knee). I think if it is switched the wrong way , it will drain the battery.
Hope this helps. Dan
Hope this helps. Dan

Can you answer why you changed the alternator/battery in the first place? Were they both bad originally. If you changed them out because of a charging problem,then the problem would be from a shorted circuit. If you charge up the battery, with the cables off, then after charging, then there should not be a load on the battery, unless you have something drawing current. Disconnect the alternator leads, just to make sure that the alternator isn't the cause. If there is a load only when the alternator is connected, then there is your problem. If there is a load and it doesn't matter with the alternator hooked up or not, then you have another drain in the system. Perhaps a light even. I would be curious as to what you find.
1975/L48/Coupe/4 Speed(1 of 1057)/Headers/true duals/aluminum intake/holley 750/MSD ignition/roller rockers/
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in Forum: C3 Electrical
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