Well, this is interesting, in a perverse sort of way. Went through the whole checklist (with the exception of checking the alternator again) and sequentially removed the fuses both from the box under the hood and the one inside the driver's side. I got a strong light on the test light for every one, except these two:
#5 - light went on, then quickly faded. This is a 10-amp red that runs the "power door lock and door lock arm/disarm switches; vanity, reading, map, rear seating, ignition and truck lights; illuminated entry; radio; power antenna (which I don't have); data link connector; body control module; and power amplifier." This sounds like the key to the problem.
#6 - Once I removed this fuse, the test light slowly "pulsed" brighter and dimmer, but never went out completely. This is a 20-amp yellow that runs the daytime running lights (Canada). I'm U.S. And I'm not even sure if I have daytime running lights. Don't know what year it became mandatory.
Now, I don't really know what a "data link connector, " body control module, " or "power amplifier" is. But here's a possibility or two--see what you think:
In late June I had a local stereo shop connect an iPod cable. They had to hard wire it because there's no auxiliary plug on the factory radio setup. I didn't have any problems for weeks thereafter (until early September), but maybe a wire has shaken loose? I haven't noticed any sound changes, however.
Also, because I have one cigarette lighter auxiliary port in the dash and one in the console, I put them to good use, keeping various items charged (GPS, iPod, etc.) On a frequent but not constant basis. Maybe there's something amiss with those systems. I stopped leaving things plugged in, however, and have still experienced the drain. So if it's that it would have to be the wiring I would think, and not the port itself.
If it were you, what would your next step be? Thanks for the tips. I'm learning more than I ever wanted to know about cars!
Sunday, October 18th, 2009 AT 5:52 PM