Weird Total Power loss - Then Back On in my E39 540

Hey Everyone,
I have a 2003 540ia with a strange electrical issue, can anyone shed a
little light on the problem?

Here are my symptoms: Every so often (ie: once per week) my 540 has a
total loss of power. Even the orange light next to the "P" is not on.
Absolutely no power, nothing, nada! Several times I have arrived at my
parked car to find the doors unlocked (luckily I park in the garage),
and once it happened while I was driving (l pulled over quickly). After
a moment or two the power is back on 100%, like nothing ever
happened..? WTF?

In an effort to determine what the hell was going on, I opened the rear
battery compartment and "jiggled" the harness to the battery. This
seemed to cause the power to go on and off, and explains why the power
comes back on as I close the door (the force jiggles the harness).
However, I have inspected the harness and battery connections, and
everything seems to be fine...?

I assume there is something I am missing in the harness itself, but
maybe I'm missing a bigger issue. Could the battery casue this type of
symptoms? What about a fuse or other electrical gremlin? Has anyone
else experienced a similar problem?

Also, my air conditioner cuts on and off intermitently (all other power
remains on). This might be a completely different issue, but I wanted
to include it just in case it is relevant to the power loss.

Thanks everyone!

In article . com>,
> wrote:
>Hey Everyone,
>I have a 2003 540ia with a strange electrical issue, can anyone shed a
>little light on the problem?
>
>Here are my symptoms: Every so often (ie: once per week) my 540 has a
>total loss of power. Even the orange light next to the "P" is not on.
>Absolutely no power, nothing, nada! Several times I have arrived at my
>parked car to find the doors unlocked (luckily I park in the garage),
>and once it happened while I was driving (l pulled over quickly). After
>a moment or two the power is back on 100%, like nothing ever
>happened..? WTF?
>
>In an effort to determine what the hell was going on, I opened the rear
>battery compartment and "jiggled" the harness to the battery. This
>seemed to cause the power to go on and off, and explains why the power
>comes back on as I close the door (the force jiggles the harness).
>However, I have inspected the harness and battery connections, and
>everything seems to be fine...?

I had this exact problem once. I took off the battery connections,
cleaned them to within an inch of their lives, put them back on
good and tight and the problem never happened again.


--
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1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
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> wrote in message
ups.com...
> Hey Everyone,
> I have a 2003 540ia with a strange electrical issue, can anyone shed a
> little light on the problem?
>
> Here are my symptoms: Every so often (ie: once per week) my 540 has a
> total loss of power. Even the orange light next to the "P" is not on.
> Absolutely no power, nothing, nada! Several times I have arrived at my
> parked car to find the doors unlocked (luckily I park in the garage),
> and once it happened while I was driving (l pulled over quickly). After
> a moment or two the power is back on 100%, like nothing ever
> happened..? WTF?
>
> In an effort to determine what the hell was going on, I opened the rear
> battery compartment and "jiggled" the harness to the battery. This
> seemed to cause the power to go on and off, and explains why the power
> comes back on as I close the door (the force jiggles the harness).
> However, I have inspected the harness and battery connections, and
> everything seems to be fine...?

You are pretty close already. Either the battery terminals are loose /
corroded or the earth strap [connection] is.

>
> I assume there is something I am missing in the harness itself, but
> maybe I'm missing a bigger issue. Could the battery casue this type of
> symptoms? What about a fuse or other electrical gremlin? Has anyone
> else experienced a similar problem?
>
> Also, my air conditioner cuts on and off intermitently (all other power
> remains on). This might be a completely different issue, but I wanted
> to include it just in case it is relevant to the power loss.

Just likely to be the thermostat.

>
> Thanks everyone!
>

In article . com>,
> wrote:
> In an effort to determine what the hell was going on, I opened the rear
> battery compartment and "jiggled" the harness to the battery. This
> seemed to cause the power to go on and off, and explains why the power
> comes back on as I close the door (the force jiggles the harness).
> However, I have inspected the harness and battery connections, and
> everything seems to be fine...?

Could be a fuseable link - known to give problems on some BMWs.

--
*If you don't like the news, go out and make some.

Dave Plowman London SW
To e-mail, change noise into sound.

Thanks Dave,
Can you tell me what a "fuseable link" is? I plan to clean and
"reconnect" the battery harness and wires at some point today. If that
doesn't work, I need to try other options...

- Ben

In article .com>,
> wrote:
> Can you tell me what a "fuseable link" is? I plan to clean and
> "reconnect" the battery harness and wires at some point today. If that
> doesn't work, I need to try other options...

It's an inline 'lump' in some cable or cables close to the battery
connection - designed to protect from a fire in event of a collision, etc,
and they've been known to go intermittent.

--
*It was recently discovered that research causes cancer in rats*

Dave Plowman London SW
To e-mail, change noise into sound.

> wrote in message
ups.com...
> Hey Everyone,
> I have a 2003 540ia with a strange electrical issue, can anyone shed a
> little light on the problem?
>
> Here are my symptoms: Every so often (ie: once per week) my 540 has a
> total loss of power. Even the orange light next to the "P" is not on.
> Absolutely no power, nothing, nada! Several times I have arrived at my
> parked car to find the doors unlocked (luckily I park in the garage),
> and once it happened while I was driving (l pulled over quickly). After
> a moment or two the power is back on 100%, like nothing ever
> happened..? WTF?
>
> In an effort to determine what the hell was going on, I opened the rear
> battery compartment and "jiggled" the harness to the battery. This
> seemed to cause the power to go on and off, and explains why the power
> comes back on as I close the door (the force jiggles the harness).
> However, I have inspected the harness and battery connections, and
> everything seems to be fine...?
>
> I assume there is something I am missing in the harness itself, but
> maybe I'm missing a bigger issue. Could the battery casue this type of
> symptoms? What about a fuse or other electrical gremlin? Has anyone
> else experienced a similar problem?
>
> Also, my air conditioner cuts on and off intermitently (all other power
> remains on). This might be a completely different issue, but I wanted
> to include it just in case it is relevant to the power loss.

Regarding the A/C problem, I recently had a problem with similar symptoms.
The blower fan would cut off by itself while the rest of the A/C unit
continued working and cooling. The fan would come on and off intermittently.
The problem was the "final stage" module for the fan. (Around $84.00 +
labor). Not sure if you're experiencing the same problem.
>
> Thanks everyone!
>