Wipers Draining Batteries?

[pseasea]

I've been trying to troubleshoot a battery drain. Tonight I finally hooked up a test light between the battery and ground. Then started pulling fuses. After pulling one at a time, nothing turned off the test light. So I figured it must be more than one, so I just pulled them all! What a pain. In the process noticed the one missing from "2 tone horn". Put one in and light got brighter, but that's another project - probalby bad horn "stuck on" or shorting that fuse. Now I've found two fuses that are draining with the ignition off. First is the wipers and second is the fuse next to it for a variety of things including heating system, mirror warmers, etc. (a 25 amp and a 7.5 amp)

First, should these circuits even be on when the ignition is off???? I noticed (by accident) that the window washer nozzle was warm earlier this evening and thought that maybe this has a heat coil in it to keep the nozzle from freezing. (it's about 90 degrees farenheit today in Atlanta).

With these two fuses out I have a very dim glow on the test light from the sound system (I assume this is the amp/cd changer, etc needing energy to keep memory, code, etc. but this is NOT the radio fuse, that's a separate one).

I'm also getting a P0410/P01411 code and was looking for a 40 amp fuse that somebody had mentioned in the forums but can only find a bank of relays above the fuse box (driver footwell). I looked behind the panel behind the rear seats mentioned in one post but no luck. Does this fuse look like a boxy relay?

THanks folks for looking at this post and replying with any thoughts.

1999 996 Tiptronic Cabriolet

[Loren]

I think a better way to measure what is acceptable draw on the battery and what is not is with an amp meter.

If you put an amp meter in series with the battery - with everything 'off' you should have a draw of about 40-60 ma. This is primarily the alarm system.

You can do the same test pulling one fuse at a time but now you will see which one is the major draw.

[pseasea]

I think a better way to measure what is acceptable draw on the battery and what is not is with an amp meter.

If you put an amp meter in series with the battery - with everything 'off' you should have a draw of about 40-60 ma. This is primarily the alarm system.

You can do the same test pulling one fuse at a time but now you will see which one is the major draw.

Loren,

Thanks, with my analog amp meter, the needle was pinned at the max with the ignition off - much more than the alarm system/radio memory. This is when I tried the light, since I was wondering if I had a bad amp guage. So, seems that I get the similar result wiht guage or test light result - very odd that the amps would be so high that my automotive amp guage would be maxed out. Yes, assuming these circuits are not bad in some sort of interrelated way, the one fuse at a time would show the differential amp draw that may be hard to detect with the guage, but I never saw the gauge move a bit during the one fuse at a time method.

When I hook up my battery charger, it seems to run forever at 4 amps which made me think that I had somewhere on the order of a 4 amp draw constantly. I need to check the range on the amp guage, it doesnt seem to have a hi/lo switch like the volts and rpm modes.

Edited June 8, 2010 by pseasea