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Discussion Starter #1
I have a '65 SS. If the car sits for just a couple of days, the battery is drained and I have to recharge it. I have tried to determine where the short is by removing fuses one at a time and testing at the battery. With ALL of the fuses out, the draw is still there. :confused: A friend suggested disconnecting the Ammeter, no luck. Does anyone have any ideas on what could possibly be causing my problem?
 

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dd,
First of all, make sure it isn't the battery itself. Get it good and charged up and then disconnect it completely. Hook it back up in a week and see what happens. I have seen them get internal "shorts".
If its not the battery, you are going to have to get a wiring diagram and see what is still in the circuit and not fused. The first thing that comes into mind is the voltage regulator itself, or maybe the alternator.
Hope this helps,
 

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Along with Bill's fine thoughts, try a method that some guys use. Disconnect the negative battery cable. Put a light and socket between the negative cable and the negative post. See if the light comes on. If it does there's something on somewhere. Can go on from there.
 

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Discussion Starter #4
Thanks for the ideas, but I've done all of that and still can't locate it. Back to the wiring diagrams....
 

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Hook up the test light as John suggested, then pull the fuses one by one. If the light goes out when you pull a fuse, you'll have found the culprit. If not, then it's "upstream" from the fuse box as Bill suggested. Or it could actually be in the fuse box.

You may even jiggle all the wires under the hood to see if the light flickers. If it does, the wire you're jiggling is the culprit.
 

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Do the deal with the light & disconnect the alternator charge wire & field wires & see if it goes out. You may have a shorted diode in the alternator. I'd also pull the battery & have it load tested.
BL
 

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Discussion Starter #7
I was doing a little bit of detective work on the car tonight and started disconnecting things under the hood, one at a time. (negative battery cable disconnected) Started with the wires to the alternator, still have the draw (about 50ma). Then I moved to the horn relay. When I took off the wires that go back to the firewall bulk head connector, the draw dropped to 0ma. I have not eliminated many posibilities except for the battery and the alternator, but I'll keep studying the wiring diagrams and let you know what I find. Thanks for your help.
 

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Then the draw is back towards the inside of the car. At this point I'd start pulling fuses again and see where it drops.
 

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50 ma draw could be considered normal. If you have a radio with station memory and a clock, that could account for that type of draw. Regardless, a conservative estimate of 70 amp-hours for your battery with a 50ma draw would last something on the order of 58 days to discharge a fully charged battery.

If all you have is 50 ma draw, then I'm betting your battery has a capacity problem. Either it is not fully charged or it is ready to be replaced. You shouldn't rely on the alternator to charge a seriously discharged battery. You should allow it to sit overnight on a trickle charger to insure it is fully charged.

If the battery has been allowed to sit discharged for extended periods, it may be sulphated to the point it needs to be replaced.

Good luck!
 

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Discussion Starter #10
Well, I'm back working on this problem again today. I have determined that the draw is on the 12 guage red wire that goes thru the firewall to the fuse pannel. So I started pulling fuses, 1 at a time, without replacing them as I went. With ALL of the fuses out of the pannel, the draw is still there! Does anyone have any advice? Are there any circuts that are not fused that I should be checking? :confused:
 

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Headlight switch isn't fused. Without yanking out that schematic believe the feed to the ignition switch isn't fused. I've seen shorted ignition switches because the case is grounded.
Might want to pop the harness off the bulkhead connector, under the hood, first. That would at least eliminate the underhood harness.
 

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Way off topic, but I gotta ask...

How'd you get the "Jolly Roger" flag, John? It's cool! :D
 

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Discussion Starter #13
I put in a brand new headlight switch a month or so ago, so I assume that's not it. I'll check the others. Thanks.
 

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Originally posted by cjlandry:
Way off topic, but I gotta ask...

How'd you get the "Jolly Roger" flag, John? It's cool! :D
I asked Dot and she likes me. Don't ca' know the women run the house. At least that's what mine tells me.
 

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Originally posted by ddroste:
I put in a brand new headlight switch a month or so ago, so I assume that's not it. I'll check the others. Thanks.
I wouldn't assume anything. Even the best quality control isn't 100% effective.

I just finished repairing a brand new Yaskawa Variable Frequency Drive that didn't work on start-up because a tiny current sensing wire was cut during factory assembly. Took me three days to find that one. That was warranty work on a $25,000 drive! :eek:
 

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Discussion Starter #17
Well, I finally found it.
I spent all day Sunday running every circuit with a friend who is an electrician. We concentrated on the non-fused items, ignition switch, head light switch, cigarette lighter, eliminating each as a possibility as we went along. Then we followed the main power wire to the fuse pannel, pulled all the fuses, and still had the draw. Then I noticed a wire that was attached to the fuse pannel on the power side that was not a power wire - BINGO! It was an after market tachometer (the kind with the memory) that was wired up wrong and had shorted out. My son drives the car and I remember him telling me that the tach seemed to be screwed up. I guess I better start listening to him a little more closely. Thanks for all of your help and advice.
 

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Great you found the answer.
*Just thinking out loud since I haven’t heard of everything*
Why would an aftermarket tach need a memory circuit? What’s it trying to remember? I can think of a connection for a light inside tied to the LMPS circuit and power for the unit to the IGN circuit but why a memory circuit tied to BAT?
 

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Discussion Starter #19
John, I really am not sure. The tach was in the car when we boutht it and I never really messed with it much and I don't have any literature on it. It is an Autometer tach with the memory recall switch on it. I'm just glad that I finally figured out what the problem was. Thanks again.
 
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