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Ground problems still exiting??? Help!
First off, ive replaced every wire harness on my 67 gto and still if i leave the batt. connected for 1 1/2 days its dead, something is drawing the charge out of it, I cannot see disconnecting one thing at a time to find the problem. Isn,t there a better way of checking it out?? When i connect my positive after my neg. batt. terminal, i see a faint spark on the post, what options do i have and does anybody have any ideas here??
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Got an amp meter?
Disconnect the negative battery cable and put the negative lead of the meter on the battery terminal and the positive lead of the meter on the negative battery cable. With everything shut off, you should read near zero or "0" milli-amps (you'll get some reading if you have a working clock or newer radio). If you're reading 50 milliamps or higher, start pulling fuses one by one until there's a major drop in your meter reading. This will narrow your problem down to a specific circuit. Most power draws are from improperly wired or malfunctioning modern stereo's. |
Pull fuses one at a time or disconnect accessories til the cable quits sparking.Electrical problems drive a person up a wall.Good luck JB.
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If you have a newer alt with the internal regulator, unplug the plug that plugs into the side of the alt and see if the problem persists, or better yet, check the current draw B4 and after for a quick indication.
if that's your problem, the two wires in the alt connector should be switched. George |
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Sorry but no way around that. --------------------------------------------- You have to find whatever's pulling the battery down. Not knowing what it is, one thing at a time is about all you can do. If you knew what it was and could go straight to it, you wouldn't be posting here. A few simple things should always be looked at first. Like: glove box/console lights, under hood & trunk lights, hanging brake light switch, stuck cig lighter, Interior lights under dash, etc. just things you can't see or wouldn't notice in the day time. A test light hooked between a battery cable end and battery post is a good way to do testing. Any short strong enough to pull the battery down should be strong enough to light the test light. With the test light hooked between battery and cable, you can pull fuses till the light goes out. Disconnect wires to the alternator without any danger of shorts and sparks. Pretty much go till you make the light go out. You don't have that much to check. Only wires and components that are hot all the time. It's just a few of the fuses, big alternator wire & plug, voltage regulator, horn relay, etc. If you think about it, it shouldn't take long to check out the whole car. If the test light doesn't burn hooked up, get the battery tested. If it's the race car project and you've got add on, non factory electronics, it may need checked also. PS Pull the courtesy light fuse while you have the doors open. All circuits mentioned above have enough resistance to light the test light but the test light wont allow enough current flow back through the circuits for anything to light up or work. |
I've learned from a rather expensive experience that a light bulb burning constantly will drain a fully charged battery in 20-30 hours. About the same time frame you are talking. For me, it was only after a tow and several hours of labor that it was determined that the trunk light switch was mis-alligned and the light was draining the battery.
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great idea,s ill try it , Thanks
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My glovebox light wouldn't go off. Took me forever to track that one down. Kept discharging my battery.
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New wiring harnesses, eh? A friend's Mustang had the same problem and we found out that the new harness installed by his brother had a couple of wires switched in one of the connectors; I don't know if the brother did it or it came that way. But the ammeter or test light or spark-watching method will get you there; you can narrow it down pretty quickly to at least a smaller area of focus.
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My 67 has no radio at the presant time, yes i have switched car over to a hei system, i have a newer style internal reg. alt. I did not know the meter and batt. check, Thanks and ill try it. I will post results on what i find. Also i have no voltage reg. on the car. Never used a meter to check voltage on the neg. side of the batt. what do i set it on?? I do know it will be DC CURRANT. Start on lowest setting?? Only other thing not connected is my horns, the wires are hanging down and not connected.
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The current draw test is not for voltage (volts), it's for current (amps or milliamps). You'll need a way to hold the meter leads in between the battery past and the cable; you are inserting it into the circuit so all current has to go though the meter. Use the highest DC current (amps) range to start with (usually 10 amps, 15 amps, or 20 amps), though if you only see a small spark when hooking up/disconnecting the battery you can likely drop down the range once you confirm it's not a big current draw.
I second Kujanski's suggestion about disconnecting the alternator as part of your investigation, maybe even first. The Mustang bad wiring problem I mentioned was due to the alternator being powered on when it wasn't supposed to be (key off). If there's no difference with the alternator small wires unplugged, you have little choice but to pull fuses one by one to narrow it down. |
I will get back to the forums soon with all my results, Thanks guys for the great answers.
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ok, guys here,s what i am getting, with positive lead connected and neg. lead off battery, i connect my amp. meter to the cable and one to the post (ON NEG. SIDE ONLY) on the 200v scale i am getting 12.2 volts,i know my bttery is charged then, right??? Now,i switch to amps on every scale i am getting o, im good so far, the minute i am putting my neg. battery lead back on im getting a very lite visual spark at the post??
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If you get a spark, but a zero reading on your ammeter, either your meter is bad or the fuse inside is blown -- my guess is it's the fuse.
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Pete, bran new meter, not a problem there, fuse?? where?? i am getting and showing voltage with my meter, its ok for sure.Just did the George thing pulled pug from alt. and still getting a spark at neg. post.
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Ammeters always (as far as I know) have a fuse inside that protects the meter and leads from excessive current. It's super easy to blow the fuse -- turning the headlights or the ignition on with the meter in the circuit will do it instantly. Also, forgetting to change the meter to read voltage after you've been measuring current will blow it if the same jacks are used for current and voltage on the meter, and you hook it up as if you're reading voltage. Measuring battery voltage with the meter set up as an ammeter is what I'm referring to -- an ammeter acts as a dead short.
I'd take a small lamp and put it in series with your meter to the battery -- make sure the meter is set to a high current range. If the lamp doesn't light (and your meter doesn't show an indication of current flow) the fuse is blown (or the meter is bad). |
Pete, i have a very good buddy who is a electrican, ill have my meter double checked and let you know the results
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try this
The best way I know to check for a draw is the simplest:
With the positive battery hooked up, put a simple 12V test light in series between the neg battery post and the neg cable. If you have a draw, the test light will be from a glow to a bright light depending on the draw. Much easier than dealing with a amp meter and the amp meter often gives conflicting results. The way to use an amp meter is between the batter and the corresponding cable in DC voltage, but I like the light. Now that you have a way to indicate the closed circuit, start pulling fuses, unplugging things, etc until the light goes out. If you find a circut that may be a problem, probe it with one end of the test light on the positive battery (or power source) and probe the wire. It if it has a ground, the test light will come on. You are looking for a weak ground. A strong ground (pinched wire) would melt the wire. A trunk light would do this, glove box light, alternator, etc... Hope this helps |
Please don,t laugh but i never heard of a 12 volt test lamp, i will head to radio shack tommarrow and ask about one. I have one you stick into wall plugs for 110 volt, again a trip to the store will help ,i have no trunk lamp on my 67 or underhood lamp for starters,
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Your local auto parts will have 12 volt test lights.
A weak spark when connecting battery cables is normal on most cars. Anything with windings and diodes (like alternator) will cause a small spark when you hook up battery cables. The alternator may have a bad diode in it, so take it with you to the parts store and have it checked out. The 12.2 volt reading, from battery cable to post, means something is turned on or at least drawing power. If doors were open when you did the test it would have caused the volt reading, unless you had the courtesy light fuse removed. Any dash light type bulb & socket, that takes two wires to work, can be used for a test light. Day and a half for the battery to go down isn't much current draw. Wouldn't hurt to have that battery tested also. FWIW 'new' doesn't mean parts are good, just means it's 'new'. |
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