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Whats on the room fuse?

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Old Jun 25, 2008 | 10:19 PM
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Default Whats on the room fuse?

Something on that fuse is killing my battery if the car isnt driven for more a couple days. Is there anything on that one thats commonly a problem?

So far checking it out I had the interior light off and the megasquirt and its harness disconnected and theres still a pretty strong draw on the battery.
Old Jun 25, 2008 | 10:25 PM
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Aftermarket radio? Aftermarket gauges? Did anybody but you do something to the car (previous owner, etc).
Old Jun 25, 2008 | 10:29 PM
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stock bose radio, no other gauges, no alarm....i really dont get it.
Old Jun 25, 2008 | 10:30 PM
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This might seem dumb, but are all of your interior lightbulbs working? Also, if you've got the bose radio, you've got a bose amp which is likely on that same circuit. It could be sticking on.
Old Jun 25, 2008 | 10:33 PM
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hmmm i didnt even think of an amp...where is that located? all the lights in the dash and the overhead light work.
Old Jun 25, 2008 | 10:35 PM
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I have no idea. Bose sucks In Nissans there's an amp at each speaker. In Toyotas there's an amp for everything but the subwoofers, then each subwoofer has its own amp on the speaker.
Old Jun 25, 2008 | 11:00 PM
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trunk light?
Old Jun 25, 2008 | 11:01 PM
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do NBs have one?
Old Jun 25, 2008 | 11:05 PM
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I don't know for sure. Just a random draw.. but def, seen it before, I know my 90 doesn't, but I had a 97 and it did.
Old Jun 25, 2008 | 11:05 PM
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no trunk or engine bay light
Old Jun 25, 2008 | 11:08 PM
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I say amp. Have you pulled the fuse and figured out what didn't work?
Old Jun 25, 2008 | 11:10 PM
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looking the at the wiring diagrams, the amp isnt on the room fuse.
Old Jun 25, 2008 | 11:14 PM
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:sadpanda:
Old Jun 25, 2008 | 11:26 PM
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Unplug the radio and see if the problem goes away.
Old Jun 26, 2008 | 10:43 AM
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...dead bulbs drain the battery!?
Old Jun 26, 2008 | 10:50 AM
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Depends on the type of bulbs. I've seen it happen before with the ones that look like AGU fuses.
Old Jun 26, 2008 | 10:55 AM
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please explain how an open circuit can cause a voltage drain. i'd love to hear more.
Old Jun 26, 2008 | 11:16 AM
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I've only seen it in older cars like the Volvo 240. The bulbs have a wierd filament that'll break enough to not light up anymore but not enough to conduct any electricity. Some of them even have a little piece of wire that connects the end terminals together. The only ones I've seen draining a battery had that wierd shunt thing in there and they somehow shorted the circuit.
Old Jun 26, 2008 | 11:25 AM
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Originally Posted by quadmasta
The bulbs have a wierd filament that'll break enough to not light up anymore but not enough to conduct any electricity.
huh?
Old Jun 26, 2008 | 11:47 AM
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Originally Posted by mikeflys1
So far checking it out I had the interior light off and the megasquirt and its harness disconnected and theres still a pretty strong draw on the battery.
Based upon this quote, I assume you're using an inline ammeter? If so, it should be very simple for you to track this one down.

The room fuse, which comes through the Main and BTN1 fuses and is hot at all times, is pretty much used only for keepalive circuits- it's only a primary supply to a couple of things. It powers:

1- ECU keepalive, L/R @ pin 1A. (page B-1a)

2- Key reminder switch and instrument cluster keepalive, L/R at pin 1F. (Page C-a)

3- TCM keepalive (A/T only), L/R at pin AR. (page H-1)

4- Dome light. This is a primary feed. L/R. (page I-3)

5- Radio keepalive, both normal and Bose (but not the amp), L/R at 1C (pages J-1 and J-2)

6- Power antenna. This is a primary feed. L/R. (page J-3)

7- The OBD-II connector, L/R (page U) Note that the old-style diag connector in the engine bay gets its power from the engine fuse.

Of all these, the power antenna seems like a very good candidate for a parasitic drain. If the limit switch has died, that tiny little motor will be trying to operate continuously.



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