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Found a drain on my battery....now what??

521 Views 5 Replies 4 Participants Last post by  JBRONCFAN
I discovered a .40amp(not milliamp) draw on my battery when my car is turned off. I popped out the fuse for my radio, lighter and clock and the draw went away. I've had this problem almost ever since I've owned my Jetta(7 years) and the clock has never worked. The radio seems like the likely culprit but I don't know where to start to find out what is drawing the power. I'm going to keep the fuse out at night which sucks because I lose my programmed radio stations. I know the radio sucks a little juice to maintain memory, but I don't think .4amps worth. Any ideas?
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Re: Found a drain on my battery....now what?? (JBRONCFAN)

I have the same problem with the radiator fan, I wired in a manual switch. other then that you might want to see if your headunit has a switch for a constant/switchable power in mode (only if it is aftermarket) My trunk light also used to stay on, check that too. not too helpful, but worth a shot.
Re: Found a drain on my battery....now what?? (JBRONCFAN)

Is it the stock radio or aftermarket? If aftermarket, it could be wired improperly. Try disconnecting the radio connector and put the fuse back in and see if the drain diminishes. It may also be a short in the clock, since you say it doesn't work. See if you can disconnect it and see if thats the problem.
Re: Found a drain on my battery....now what?? (VWCaddy)

Well, the radio won't go on unless I turn the car on and requires next to nothing power to maintain it's memory. Clock hasn't worked for as long as I've had this problem, how can I disconnect the clock and test?
Re: Found a drain on my battery....now what?? (JBRONCFAN)

I was workign on a 92 explorer that was having a parsitic draw on it with the key off also. I can't rememebr exactly what the draw was, but it was way too much, enoguh to kill the Bat in two weeks, anyway when ever trouble shooting:
1) Verify complaint
2) Generalize to system
3) Localize to sub-system
4) Isolate component
5) Repair
anyway you have generalize to the system already by pullign a fuse replaceing it and pullign another, untill you found one that the current draw was passing through, now with say wireing diagrams you see what systems run on that coud be many thus a sub-system, then from there you test each peice individualy lookign for this paracitic draw, till you localize it. In the case with that Exploder it turned out to be in the ECC, then upone a closer inspection a relay that was corroded where the points where bridged so the switch inside that is close with the magfnatic feild was closed all the time with out the magnatic feild letting current pass thought with the key off, i changed the relay and retested and teh parasitic draw was gone.
i hope this gives you some ideas

[Modified by IronGTi, 2:49 AM 4-8-2002]
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Re: Found a drain on my battery....now what?? (vedubya)

Like I said, my radio is wired to the ignition and can't turn on without starting car. I'm leaning toward the clock which hasn't worked the exact same time I started having this problem years ago. Does anyone have experience working on the dash clock in a Jetta and how can I get to it?
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