annoying short

[Necrocom4]

i have this issue of the battery slowly being drained when the van is off. when i took it for inspection last year the guy comes back in the waiting room and tells me it wont start. he jumps it and pulls out his dvom on it while its running. runs at 14 something volts. then when he turns it off the voltage slowly drops like 0.01 volts every 4 seconds. he said he didnt have time to find the short but he said the alternator seemed fine cuz it was charging. well aside from that problem they passed it after i told them id bring it back to let them find the issue. i thought i could find it myself though.

when i got home i checked it when it was running and it read 14. i turned it off and the voltage stayed at a solid 12.40. i let it sit for about 3 days checking it every day and the voltage still stayed at 12.4. i didnt think the problem fixed itself but i didnt know what else to do. i didnt think i was gonna be able to find the short if it didnt show itself so i kept driving it for 4 months with no problems. i took it off the road in november cuz i kept having to ask coworkers for jumps and the last time i drove it the thing stalled out in the middle of an intersection.

this month i wanna put it back on the road. i had the battery charged and when i hooked it back up that short showed up again. about 0.01 volts going down every 4 seconds. determined to find out wtf was going on i grabbed my dvom and started the van. ran at 14v fine. turned it off and the short seemed to disapear again. frustrated i drove it around the block 4 times in an effort to see if any loose or rotted wires were being grounded out somewhere. when i checked it again the voltage stayed at 12.2. i checked the next morning it still read 12.2. i check the thing in another 3 days and it still read 12.2. then i let the thing sit for 3 weeks. i go out and check it and the volts read 9.7.

the short seems to be draining very very slow. i read that when alternators get old they can sometimes short themselves out and still charge the battery. i dont wanna spend $80 on one if thats not the problem though. and i dont really wanna pull it out just to find out its fine. this is really the only issue with this thing that keeps me from putting in on the road. if i cant solve it soon i can look forward to getting into a place with a garage in the next month and then start stripping everything like i wanted to do.

[rlsllc]

Batteries can also short themselves out, and it can be intermittent. If you can, try a known good battery in the van, and the battery in question in another vehicle.

[LiftedAWDAstro]

Another thing to do is pull a couple of suspect fuses when you park it and see if the voltage drops. Doing this will narrow down where the draw is. Do you have access to a DC ammeter? If so, check each circuit for current draw.

[Smiliesafari]

I'm inclined to go with the bad battery theory. If there were a dead short, after sitting three weeks, it would take the voltage to "0".

[Necrocom4]

the van came with a battery that was dead. it didnt hold a charge so i bought a new one. i did try the fuse thing and it didnt do anything. i took the battery out and im gonna let it sit for awhile to see what the voltage does. its still reading 9 but we shall see in a couple weeks. i almost went and bought another battery awhile back just to be sure but when i got it charged at autozone the dude said it was completely fine. i just kinda took his word for it.

[LiftedAWDAstro]

I see you are in Williamson, NY. You need to get your van fixed up and join us at NECO in Wolcott...practically in your back yard!

[mdmead]

If your battery is at 9 volts now, I'd charge it ASAP and not wait for it to go any lower. That is hard on a battery and will shorten its life. (Once it up above 12 again, you can still watch it for discharge over time.)

Also, it doens't sound like you own a battery charger.... buy one!

Dean is right in that by pulling a few fuses, you can probably trace the problem. It sounds like it is taking quite a bit of time for the drain to show itself, so I'm thinking when you pulled fuses before, you may not have waited long enough.

And finally, have you considered buying a battery diconnect? I picked up a couple of cheap ones at a roving tool show about a year ago for just a couple of bucks apiece. While it isn't the most convenient option, it sounds like a good way to get your van back on the road in the short term.

[rlsllc]

A couple of questions:

Do you have any of the following:

Aftermarket Stereo, amp, EQ, etc

Trailer light wiring

Extra 12v outlets anywhere

Any extra lights, like fog, etc

Any other non stock or added anything

Have you checked at night, in the dark, that no interior lamps, glove box or dash lights are staying on, even a little from a bad switch?

I've seen a trailer plug corrode and the pins short enough to drain the battery but not blow the fuse.

Aftermarket stereo stuff is often poorly installed, I always check that stuff when I buy a used van. I've found twist-and-tape, wire nuts, scotch (like clear) taped connections, all kinds of crap. Same goes with fog lights and stuff.

[Necrocom4]

well ive been letting the battery sit for the past week and checking it every day. its been sitting at 10.30 volts the whole time. i just went outside and removed the dome bulbs and took the stereo out. the power wire for the stereo was shoved into the fuse panel. i took it out just to be sure. theres no trailer wiring. as far as i can tell it never towed anything. no signs of a hitch is anywhere in the rear. im gonna put the battery back in to see what happens over the next few days. i really feel like pulling every single wire out of the whole van. i guess ill save that for the tear down when i do it.

i just noticed that the e-brake wire wasnt plugged in under the dash. doesnt seem to be doing anything though.

[v8famvan]

I have to locate drains on vehicles all the time as I am a GM automotive tech, so I could relate how I find them.
The best way to identify the source of a battery drain is with a DVOM - multimeter that has an ammeter in it. Decent quality meters have a 10 amp capacity fuse in them which is used to perform this test. Connect the multimeter leads between the positive terminal of the battery & the positive cable with the meter set on the amperage position. At this point, all the amperage required to power up the vehicle will be flowing thru the meter.
CAUTION: If you activate any circuit or device at this point you will be increasing the amperage flow thru the meter and could surpass the capacity of the fuse in the meter. Example: Opening the door at this time will cause all the power required to turn on all the interior/dome lights to flow thru the meter.
Typically, when you have the meter set up in this way you should see less than 25 milliamps draw on a unmodified vehicle. On vehicles with aftermarket accessories you can expect to see some increase from this basic spec. but still should not be over 50 milliamps. If you do have excessive amperage drain then start to pull fuses to identify the circuit that is causing the drain.
As rlsllc mentioned, a good visual inspection of the vehicle for items that are left on/turning on is a good idea. Like looking for a light in the dark.....Do you have lighted vanity mirrors in your sunshades? This is a very common area of concern in GM vehicles. ie: broken covers, switches, items jammed into them causing the lights to stay on.
Hope this helps some.

[Necrocom4]

not to be retarded or anything but whats the amperage setting on the dvom look like? i have a craftsman 82140. it has Vdc, Vac, Adc, 10A, Bat, and Ohms. oh and the little buzzing thingy you use to see if theres a circuit. i bought one last year after a freind told me they were very useful but as far as actually understanding all of the settings i dunno yet.

[LiftedAWDAstro]

You are looking for the ADC section. Start on the 10A setting and go down from there. Put the RED lead in the RED plug and put the BLACK lead in the 10A plug and if you switch to the 200 mA setting you need to move the black lead. If you are reading under 0.200 amps, switch to the 200mA setting.

[Necrocom4]

alright thanks guys ill try it tomaro after work. its impossible to see it draining from just watching the voltage so this method sounds like itll work better and be alittle more specific.

[Necrocom4]

i blew the fuse on the meter my dumbass set it on amps and connected the the leads to the positive and negative terminals on the battery. first time for everything i guess.

[v8famvan]

Yup....connecting it up that way is a quick way to blow the fuse...

Not the first to do that......