Bad battery or generator?

If you remove a cable from the battery and hook the circuit tester between the cable and the battery post that it came off of and the tester lights up,either a hot wire is grounding out or something in the car has been left turned on.You might want to check things like the dome light or dash lights.Other than that,start pulling fuses one at a time to narrow it down.
Good luck.
 
If it's original, there is only one fuse. But it sounds like this car has a lot of modifications, so who knows.
 
Okay so I did what a few of you said. I ran the circuit tester from the neg post to the neg cable and pulled every fuse until it turned off. I found the circuit issue it’s the BAT3 STOP CTSY spot however how do I further diagnose the problem and find the culprit?

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It is going to depend on how it is wired. But it is mostly in the brake light or dome light circuits. Do you have the wiring diagram?
 
It will be hard to tell how it was wired up probably the only way is unhook one thing at a time to see if the light goes out then you will know when you find it
 
So I have three wires going to my brake switch.

Looking at the diagram that flatheadTed posted one of the orange wires goes from the STOP / CRTSY spot to the brake light switch, the other orange wire goes from the brake light switch to the dome / CTSY light then turns into a white and black wire that goes from the light to the headlight switch. The diagram says the black and white wires goes to the dome / CRTSY ground.

If there’s a live wire would that mean that particular ground would be bad or loose? How do I check these connections?
 
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I would disconnect one wire at a time and try to isolate where the problem is. Start at the light switch, then the dome light, then the brake switch.
 
JSeery said:
I would disconnect one wire at a time and try to isolate where the problem is. Start at the light switch, then the dome light, then the brake switch.
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Okay, so let me ask you how do I use the circuit tester correctly when disconnecting wires?

Should the fuse for that circuit be in or removed? What am I looking for when I disconnect each wire? Will the light remain on or shut off? This part cunfuses me.
 
Hook it up to the battery like you had it. Fuse in place. You are looking for what will make the light go out.
 
The brake light is generally always integrated into the turn signals too if your car is so equipped. It boils down to how well all the wires and switches are insulated from the ground when they are hot all the time. Your set up is like a modern car. You might look for American Autowire information on that model of wire kit since that's what it's all wired up with. They should have a general schematic. There are several companies that manufacture aftermarket rewire kits for the folks that want to update an older vehicle to modern electrics.

Lights are generally wired to be hot all the time whether the key is on or not. If there is some form of short or component like even a resistor or small light bulb that is hot all the time, it will drain the battery over a short period of time. Clocks can slowly drain the battery if it is hot all the time to eliminate constant readjustments. A small worn through spot on a wire can short to ground or another wire and cause a current draw but they will generally blow a fuse if it becomes a direct short to ground. If there is no fuse on the wire it will burn up if it shorts to ground. Fuses are there to protect the wiring.
 
Ya I finally noticed that. Some dome light grounds are set up to be worked by opening or closing the doors. I had a modern car that would drain the battery due to an intermittent short to ground on one door switch that would cause the dome light to come on whenever it wanted to. I caught it with the battery drain check by pulling fuses. One of the dome/courtesy lights was burned out so it wouldn't work but the other one had fallen down a bit behind the trim panel so you couldn't see that is was on until the dark of night. The battery was always dead by morning when that happened. Fixed the ground switch and the lights and no more drain.
 
Best advice I can provide would be finding someone that is good at electrical trouble shooting. If it's not something simple or obvious at this point it could be somewhat challanging to find.
 
The test lamp circuit tester you are using is really meant for testing for power between ground and battery power and not for testing current drain (amps) which is how you are using it. To test for drain then a multimeter set on amps will give you a much better idea of what the actual drain in amps is. If your car has modern electronic items fitted such as a radio/tape/cd player then the drain (very small in milliamps or fractions of one amp) may be what is causing your test light to come on. I see you have an alternator and electronic ignition fitted so these could be the cause of a tiny leak. Anything electronic can have a tiny leak which might be normal. So get hold of a digital multimeter and set it to amps (you might have to move one of the test leads into the Amps socket to read amps) and that way you will know the actual current draw which might be very very small as in a fraction of an amp and therefore nothing to worry about. Connect the meter the same way that you are connecting the test light. Regards, Kevin.
 
Oh, by the way you asked how the test light works, well if it is ON then there is a drain and if it goes OFF then the drain has been eliminated. You should disconnect one electrical unit at a time until your light goes out as in the radio or the alternator or the electronic ignition unit or anything else which has modern electronics inside. Regards, Kevin.
 
koates said:
Oh, by the way you asked how the test light works, well if it is ON then there is a drain and if it goes OFF then the drain has been eliminated. You should disconnect one electrical unit at a time until your light goes out as in the radio or the alternator or the electronic ignition unit or anything else which has modern electronics inside. Regards, Kevin.
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Hmm, I thought that when I pull the fuse if the light goes out that’s the drain. Every single fuse the light stayed on when I pulled them except the one I mentioned.
 
Solo_909 said:
Hmm, I thought that when I pull the fuse if the light goes out that’s the drain. Every single fuse the light stayed on when I pulled them except the one I mentioned.
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That's what I said only in a different way, so re read my post again. Do this.... refit that fuse back in its holder and start disconnecting things, starting by disconnecting all the wires to the stop light switch and make sure they are separated from each other. How many wires are on that stop light switch ? Report back your findings.
 
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