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Old 18 May 2005, 06:55 am
remco
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Default Re: Battery draining

>
> After taking all of your advice, we found nuthin!
>
> BUT, there is this blade fuse in line with a wire
> coming directly off of the positive terminal of
> the battery. Apparently, it feeds the fuel pump
> relay. Its a 30 Amp fuse.
>
> Anyways, when I pulled that fuse, the draw on the
> battery went from 0.87amps to 0.01amps. I'm
> thinking my problem is there.
>
> Any ideas on how to fix this? Once the power goes
> to the relay, where would it go from there?


Seems odd that they'd fuse a fuel pump with 30Amps and feed it directly off
the battery since a a fuel pump doesn't take very much power to run. Power
delivery (ie power drop across wires, requiring fat wires) is usually not a
problem.

My old volvo was an older model and don't remember if they had direct line
going to the pump.
What is more logical is that this fuses the alternator. An alternator is
usually directly connected to the battery. It does have diodes inside that
short and cause current to flow when it shouldn't. Can you follow that wire
to see where it goes?

Also, I'd imagine that if that fat wire and fuse indeed do feed the pump
through a relay, it would most likely be connected to the contact of the
relay (the switch side) -- there's no point connecting a high current wire
to the coil (actuator side) of the relay as that is definitely low current.
That being true, the only way that you can have any appreciable current
running is if the pump is running, even with the car shut off. That relay
must be driven somehow.

I'd still first check to make sure that that fat wire/fuse is not connected
to the alternator, though..

Remco



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