When the 505 loses electricity and the battery goes flat while sitting around

luthier

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My STI has a parasitic power drain which flattens the battery after about 48 hours.
The first thing was to check the alternator diode, a simple test between the case of the alternator and the output terminal which should only pass power one way. That's OK so it's not the issue.
On the fuse board there are three fuses that carry a constant power with the ignition switch either on or off.
I suspect one of these. A friend suggested eliminating by removing one at a time to see if the battery drains. good theory except it would kill the battery if it happened a few times before diagnosis.
So I'm almost ready to take it to the auto sparkies cause they always seem to isolate stuff really quickly.
But just on the offchance I thought I'd mention it here in case someone has a blinding illumination for me.
Cheers.
 
Don't wait for the battery to go flat. Just pull each fuse and put an ammeter across the terminals. To drain a battery in two days would probably be in the hundreds of mA.

Have fun,

Rob.
 
My 504 went flat because I had wired the new radio to bypass the ignition - so I could use it whenever. Small drain because its computer needed to stay alive and remember things...I now have a separate switch to allow the 12V only when I'm using the radio. I'm a slow learner.
 
Similar to a couple above. The CX that we had a few years ago we upgraded the stereo in it and I didn't quite follow instructions. There were two positive power feed wires - one a small gauge and the other a larger gauge. The smaller one needs constant power supply to maintain settings memory - I recall I'd sort of stuffed something up there and this was causing power drain that would flatten the battery in a couple of days of the car sitting in the garage.

Once I sorted that out we never had another problem with battery drain.
 
I'd check out the boot, interior and glove box lights first. :wink2:

When I had my 505, the boot light was the cause of a flat battery every few days. Just one of those dumb things you never check!
 
I reckon my first problem is my bloody stupid meter that I got from Wotalotacrap Auto. i don't believe that the ammeter actually works.

Akshully I know it doesn't work because it shows nothing when the boot is open and that light works. So all amp tests are not valid.

And the damn thing cost about $60 or so, I forget. I'll need to get a really cheap $20 one so I can do some proper testing.
 
Probably a blown fuse. Often there are separate fuses for low and high current and the rest of the meter can function fine when the high current one's blown, but amps won't work.

Have fun,

Rob.
 
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