My battery after full charge will discharge if car sits (not running). I know it's not the battery as I just purchased a new one. Could a faulty external voltage regulator be a posible culprit? I have the standard HD alternator (car has AC) with the external VR. I pulled the VR off and it wasn't a factory Delco-Remy one being much lighter without any markings other than a part number. I have a used VR (factory Delco-Remy) from a '70 350 Skylark car I scored from a junkyard- are they the same as on the 455 cars? Car has no memory settings or killer aftermarket radio- only stock AM /FM one. Something is draining battery. Just wanted some ideas before I start troubleshooting a possible bad ground? I did take some voltage readings with the two VR's with car sitting with terminals attached at batt, running at idle, and at 2000-2500 RPMs. I can post them if that will help diagnose my problem.
I don't know about your car, but on mine to light in the glove box was staying on doing the same thing- draining the battery down, Just a thought make sure all your lights are off including brake lighst(sometimes switch sticks). Just one suggestion.
Along Dan's line of thinking, last summer I found that my interior lights were no longer turning off when I closed the doors, figure I have a bad door jamb switch I need to replace, so I've temporarily pulled the fuse out. It was hard to notice, since I don't typically drive the car at night. Sorry I don't have any advice on the VR's.
if you have an old analog voltmeter do the following. unhook the positive terminal and put it in line between the battery and the cable. It should register a voltage if you have a voltage draw. Unplug your alternator and see of the voltmeter registers different. then go to the fuse block and start pulling fuses, checking the voltmeter after each one. When you get to the right circuit, the voltmeter will go to zero after pulling that fuse. Now you can hunt down where the touble is. good luck!
Thanks for the responses fellows! I do know that all the interior lights work and turn off as they should. Only one I have a question about would be the trunk light so maybe I need to get in there and have my wife shut it (unlock it too! p ) and check to see if trunk light is going off. I will need to check that glove box light too. Adam- could I do the procedure as you described with a digital voltmeter? I don't have an analog one.
The glove box and trunk both have ways to check without fully closing them. Thereshould be a button in the glove box that works the light. The trunk light goes on and off as the lid is opened and closed. At night, open the lid then kneel down as you close the lid, once you get down to about 6inches left before closed, the light should be off. Do what Adam suggests with the meter and see. I'd bet when you unplug the alternator the drain goes away.
go to the fuse box and do the voltmeter test on each circuit one at a time. all you need to do is pull a fuse and test the 2 terminals that the fuse came from ..... if no votage is passing through, put the fuse back and test the next one .... eventually you will track down the circuit/circuits that were probably draining your battery.
Because most digital voltmeters have virtually infinite resistance, I don't think it will work. You can try and test to see, but I have been told that say a Fluke meter won't do it. You might be able to use the amp mode, but chances are that your draw will exceed the amp rating of the meter, unless it goes to 10 A or so.
update...... Car battery was dead last night so I still have a short and/or parasitic drain that is discharging the battery. I couldn't find my glove box light- it may be behind liner and will look when I can. Was it mounted at top of box? Did see the switch that the box trips to shut it off. I got in car, shut doors, and pushed that switch but nothing happens- no light or anything. Can someone also tell me about the ashtry light? Mine isn't working but I found that small cylindrical like aluminum pice attached to wiring- is that the bulb and where does it mount? At this point, I need to break down and purchase an analog voltmeter and will check out Harbor Freight's selection. What features on this unit do I need to do the in-line testing as Adam described? Haven't had a chance to review fuses at this point but will do so. Keep any feedback coming that will help aid in this situation. I really want to get this car back on the road- seems like as quick as I fix one problem, another develops! ou:
This may sound weird but when I got my Skylark it had the same problem and a local mechanic told me to unplug the wire on the cigarette lighter, problem solved. You should be able to get a analog volt/ohm meter at Radio Shack for $10. Dave Berry
The glove box light should be right behind the button. On the left side panel towards the top. The ashtray light is attached to the wire itself, take some pliers and pull the cover off the base as it's a two piece assembly. When the covers removed, you'll get the bulb. hth
yea my sister used to throw change in her ashtray ..... her lighter recepticle was nearby with no lighter in it ..... one of her pennies went into the lighter hole and she didnt know it and her battery began doing what you describe ... it would drain over night .... sometimes not ....... then one day she hit a bump in the road and the digital clock messed up on her radio, interior lights stopped working, and power locks quit too!!(chevy lumina). everytime she touched a new fuse into the block it would blow ... after my brother in law had scratched all the hair off his head tryin to figure out what went wrong, my nephew was lookin around in the car and happened to notice the penny in th lighter hole ....PROBLEM ELIMINATED. CLOCK SUSPECT: does your car have an anlog clock that no longer works? sometimes the "points" inside them stick on (usually from an old rotted capacitor) and drain batteries. if your clock dont work but the plug sparks when you plug it in or unplug it, it very well could be the problem. BATTERY TEST: just to be on the "for sure' side. unhook your (charged) battery and let th car set for a day or two. hook it back up and then see if it ends up being drained. your new battery might have a problem ... it wouldnt be the first time. keep us posted!
Yuk: no factory clock in this car as it was removed and replaced years ago with one of Y1's factory appearing in-dash tachs. It is definitely not the battery as I had done what you described with a full charge outside of car- battery will keep it's charge for days when not hooked to terminals on car. Recently bought a new Champion battery too and it killed that one after two days in the car sitting and hooked up. I know now where NOT to look for an analog voltmeter- Harbor Freight! Only had one model and it was digital. I'll go by Radio Shack unless one of you have a better suggestion. Cyberbuick: thanks for the tips on locating the glovebox light. Didn't get a chance to work or look at it yesterday. Still going to try that tip on unhooking the lighter.... Keep the tips and help coming guys- I appreciate it!
Re: the parasitic battery drain with car sitting- here's latest update: I took my new analog multimeter and put it in-line between positive battery post and positive post of battery. I measured voltage at 12.5v. Unplugged alternator- no drop in voltage. Pulled each fuse one-by-one and chacked for any voltage drop- none seen! Votage stayed consistent at 12.5v Checked glovebox light switch which was intact but no bulb there-consulted manual for bulb type, had one on hand, and light works fine. Also goes off as it should when glovbox door shuts. Lights in side compartment area in interior go off when jamb switch/ doors shut. Ashtray light appeared blown and will be replaced once I purchase another. Anyone know how that light attached to ashtray? Mine was dangling and I couldn't find how to attach in manual? My next step was to disconnect wire plug at cigarette lighter and see if that works to help with battery drain. If that doesn't cure drain, I plan to disconnect and take out fuse to radio to see if that matters. I can also take out alternator and have it chacked at a place like Advance or Auto Zone. Big thank you to my friend Russ Waters who called yesterday and gave assistance into this concern. One other quick question: with a quick disconnect battery switch- should it go on positive or negative post at battery? Anyone else have any ideas on my problem???
The ashtray light just clips to the dashboard from underneath.. Take the ashtray out and look up at the edge of the dash there where you removed the tray. You should see a square/retagular shape cutout with flap type edges. Take the light and just clip it back in.. Did you try taking the multimeter to the fuses themselves? Putting on the battery I wouldn't think would show anything as your drain is probably a small one that take all night to do it's damange.
Did you disconnect the big wire on the back of the alternator too? If it has a bad diode that can do it. Also unplug the voltage regulator. Not to insult your intelligence, but is there an underhood light? Keep plugging away, you'll find it. The ashtray light should only be on with the headlights/dashlights.
I know this problem from experiance. I got rid of the external regulator and had the alt. rebuilt to an internally regulated 105 amp output. Since you didn't mention that you had done this I can only assume that the problem may be at your regulator like you origionally thought. If the wireing to it is still the origional I don't have any thing to add. If you have changed any of the wireing the regulator may be staying on draining only 1/2 of an amp per hour. This very likely won't show up on your meter. Try and disconnect the regulator and see if the battery drains over night. If not problem solved. The regulator is bad or the wires going to it or to the Alt. are crossed. Check to make sure the wires going to the Alt. are not loose and are connected properly. If the nut that holds the positive wire onto the Alt. is loose you could be shorting out. I don't know if any of this will help but it solved my problem and all I had to do was change the wires going into the Alt around and it was fixed. I usually took 2 or 3 days for the battery to go dead but I also have a gell cell that holds a charge for a longer period of time. Good Luck.
Try pulling all of the fuses, one at a time. The one that arcs as you reinstall it will show which ircuit has the drain on it. Obviously it'll have to be a little dark while you do this, but it works.
A bad alternator diode will cause what you're experiencing. Just as an experiment, maybe you could try charging the battery and reconnecting it, then wait a while, maybe an hour or so, and then feel around on the alternator. If it's warm, you've may have a bad diode. Or disconnect the alternator and check ohms between the output terminal and ground, should be very high, 300K ohms or more.
