Amp draw
09-14-2012, 07:41 AM
#11
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It will skyrocket when you pull the fuse on the circuit that has the dead short to ground in it. If you have a dead short to ground, you should read very low resistence...probably less than an Ohm. It's like puttting the two probes of the multi-meter together. They complete a circuit, and you'd read 0 ohms. With a 30 amp draw, that's probably what you have somewhere in your car. On some circuit ground and positive are shorted together sucking your battery dry. A healthy B5 will read very high resistance between + and - because the only thing completing a circuit is the radio anti-theft stuff and the remote locking/theft stuff, and there is a lot of circuitry between + and - in those systems. You have a circuit that is essentially connecting the + and - on your battery. That's the circuit you are looking for.
09-14-2012, 01:43 PM
#12
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Yes, you're looking for ohms across the disconnected battery cables. If the dead short is on the other side of the fuses, it should disappear when you pull the fuse. I forgot about how high your amp draw is. If you're really drawing 30 amps, that pretty much limits the search to fuses over 30 amps. That is a huge draw though.
09-15-2012, 06:28 AM
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OK, The ohms check between the battery cables is zero, like the two probes touched together. Now, I disconnected the additional cable that connects to the positive battery cable (looks like it goes inside the vehicle), and checked the ohms between that small cable and the negative cable, and it was zero also. However; when I checked the ohms between the large positive cable with the little one disconnected, and the negative cable, I got 92,000 ohms! Not sure what this tells me, but I am pretty sure 92,000 is not normal. Maybe this is not an accurate test with the little cable disconnected?? The large cable appears to go down towards alternator and starter.
09-15-2012, 06:32 AM
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OK, The ohms check between the battery cables is zero, like the two probes touched together. Now, I disconnected the additional cable that connects to the positive battery cable (looks like it goes inside the vehicle), and checked the ohms between that small cable and the negative cable, and it was zero also. However; when I checked the ohms between the large positive cable with the little one disconnected, and the negative cable, I got 92,000 ohms! Not sure what this tells me, but I am pretty sure 92,000 is not normal. Maybe this is not an accurate test with the little cable disconnected?? The large cable appears to go down towards alternator and starter.
09-15-2012, 01:59 PM
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...checked the ohms between that small cable and the negative cable, and it was zero also. However; when I checked the ohms between the large positive cable with the little one disconnected, and the negative cable, I got 92,000 ohms! Not sure what this tells me, but I am pretty sure 92,000 is not normal.
By the way, I just checked mine for the heck of it. With both cables disconnected, I get about 1,900 ohms for a half a second, then it goes outside the 2000 ohm range of my meter. Remember, high ohms are not what's draining the battery. It's the 0 ohm reading.
Last edited by mtroxel; 09-15-2012 at 02:02 PM.
09-16-2012, 07:36 AM
#18
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What's not normal is the 0 ohms. 0 ohms between the positive and negative means a dead short....positive is connected to ground...........really well. That's what's killing your battery. And if it's on the cable that goes into the car, you've already started to isolate the circuit that is draining you. I believe that big cable that goes toward the front ends up right on the alternator, so that's probably not the problem. Pull it off the alternator just to hit that pitch out of the park, but I think your problem is inside the car. Now you just need to start pulling fuses (probably a really big one if you've been drawing 30 amps) to find the cirucit where your problem is.
By the way, I just checked mine for the heck of it. With both cables disconnected, I get about 1,900 ohms for a half a second, then it goes outside the 2000 ohm range of my meter. Remember, high ohms are not what's draining the battery. It's the 0 ohm reading.
By the way, I just checked mine for the heck of it. With both cables disconnected, I get about 1,900 ohms for a half a second, then it goes outside the 2000 ohm range of my meter. Remember, high ohms are not what's draining the battery. It's the 0 ohm reading.
09-16-2012, 08:24 AM
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There ya go! 0 ohms means you might as well have a cable that connects the + & - posts or your battery. Maybe you pull every fuse in the little fuse box on the end of the dash. If you still have 0 ohms, you can rule that whole thing out. Then you have the fuses and relays behind the knee bolster under the steering wheel.
09-18-2012, 05:02 PM
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I believe the culprit has been located. I was testing the cables that are connected to the power distribution under the dash on drivers side, and finally located one that made the ohms jump up. It appears to be the passenger power seat. Although the driver side seat was working, I never did try the passenger seat. Sure enough, the passenger seat control switches were toast. I can see with a mirror that the backside of the controls is black and toasty. Now to find out why. Thanks for all the help on this one. I couldn't have done it alone. Cheers.
TommyJ
TommyJ