OT-auto electric sleuthing help

The YukonXL's (love that "XL" part) battery went dead a few days ago.
In the process of diagnosing why, I found there's a 1.3A* load on the
battery when the key is off. Doesn't seem right, does it?

So, I went through the process of removing every dang fuse, one at a
time, in both panels while I had a light-em-up circuit tester in
between the neg. battery terminal and the neg. battery cable. The load
stayed up despite pulling every fuse with one slight wrinkle. There
are 2 fuses marked PDM and DDM (Passenger Door Module and Driver Door
Module--I'm guessing these are the keyless clicker black boxes that
lock and unlock the doors from the remote). When I removed either of
these fuses there was an audible clicking almost like a turn signal
click, and I could see the lamp in the circuit tester flashing. Put
the fuse back in and the clicking would stop. However the light in my
tester (and hence the load) stayed on the entire time whether or not
the fuse was in place.

I could also hear a very slight click and then hum from somewhere near
the firewall whenever I connected the tester, and a few seconds after
I removed the tester another very slight click and the hum would stop.

Anyone have some advice as to what's going on?

What could cause a current draw like this that doesn't go through a
fuse or the ignition switch?

--
Charles
'99 YZ250

"HardWorkingDog" <harvey@mush.man> wrote in message
news:harvey-92E11B.21434826112007@individual.net...
> The YukonXL's (love that "XL" part) battery went dead a few days ago.
> In the process of diagnosing why, I found there's a 1.3A* load on the
> battery when the key is off. Doesn't seem right, does it?
>
> So, I went through the process of removing every dang fuse, one at a
> time, in both panels while I had a light-em-up circuit tester in
> between the neg. battery terminal and the neg. battery cable. The load
> stayed up despite pulling every fuse with one slight wrinkle. There
> are 2 fuses marked PDM and DDM (Passenger Door Module and Driver Door
> Module--I'm guessing these are the keyless clicker black boxes that
> lock and unlock the doors from the remote). When I removed either of
> these fuses there was an audible clicking almost like a turn signal
> click, and I could see the lamp in the circuit tester flashing. Put
> the fuse back in and the clicking would stop. However the light in my
> tester (and hence the load) stayed on the entire time whether or not
> the fuse was in place.
>
> I could also hear a very slight click and then hum from somewhere near
> the firewall whenever I connected the tester, and a few seconds after
> I removed the tester another very slight click and the hum would stop.
>
> Anyone have some advice as to what's going on?
>
> What could cause a current draw like this that doesn't go through a
> fuse or the ignition switch?
>
> --
> Charles
> '99 YZ250

Charles,

I would approach it with an ohmmeter, that sounds like a ten ohm load on the
battery. Measure from the disconnected positive battery lead and see if you
see the ten ohm load. If not, it is some relay operated load, or maybe the
On-Star system is ordering out.

If you see the ten ohm load, again pull the fuses. Partially failed
recifiers in the alternator could be an unfused culprit, but I think all the
electronics in today's vehicles are fused.

What about the trailer light kit, is it aftermarket or oem? The aftermarket
one I put on my Toyota would blow the fuse all by itself, when it felt like
it.

Happy hunting!

Joe

XL600R

In article <figd3f$67o$1@aioe.org>,
"Joseph Rooney" <ikerooneyat@pcmagic.net> wrote:

> "HardWorkingDog" <harvey@mush.man> wrote in message
> news:harvey-92E11B.21434826112007@individual.net...
> > The YukonXL's (love that "XL" part) battery went dead a few days ago.
> > In the process of diagnosing why, I found there's a 1.3A* load on the
> > battery when the key is off. Doesn't seem right, does it?
> >


> >
> > What could cause a current draw like this that doesn't go through a
> > fuse or the ignition switch?
> >

>
> I would approach it with an ohmmeter, that sounds like a ten ohm load on the
> battery. Measure from the disconnected positive battery lead and see if you
> see the ten ohm load. If not, it is some relay operated load, or maybe the
> On-Star system is ordering out.

Thanks, but no On-Star. The black helicopters are quite enough.

A relay-operated load, meaning, the relay is staying closed when power
is off? Can I yank the relays off the panel just like a fuse? I'm
skeered to pull on 'em too hard.

>
> If you see the ten ohm load, again pull the fuses. Partially failed
> recifiers in the alternator could be an unfused culprit, but I think all the
> electronics in today's vehicles are fused.
>
> What about the trailer light kit, is it aftermarket or oem? The aftermarket
> one I put on my Toyota would blow the fuse all by itself, when it felt like
> it.
>

OEM trailer wiring.

> Happy hunting!
>

Thanks!

--
Charles
'99 YZ250

"HardWorkingDog" <harvey@mush.man> wrote in message
news:harvey-3B1BB8.22395826112007@individual.net...
> In article <figd3f$67o$1@aioe.org>,
> "Joseph Rooney" <ikerooneyat@pcmagic.net> wrote:
>
> > "HardWorkingDog" <harvey@mush.man> wrote in message
> > news:harvey-92E11B.21434826112007@individual.net...
> > > The YukonXL's (love that "XL" part) battery went dead a few days ago.
> > > In the process of diagnosing why, I found there's a 1.3A* load on the
> > > battery when the key is off. Doesn't seem right, does it?
> > >
>
>
> > >
> > > What could cause a current draw like this that doesn't go through a
> > > fuse or the ignition switch?
> > >
>
> >
> > I would approach it with an ohmmeter, that sounds like a ten ohm load on
the
> > battery. Measure from the disconnected positive battery lead and see if
you
> > see the ten ohm load. If not, it is some relay operated load, or maybe
the
> > On-Star system is ordering out.
>
> Thanks, but no On-Star. The black helicopters are quite enough.
>
> A relay-operated load, meaning, the relay is staying closed when power
> is off? Can I yank the relays off the panel just like a fuse? I'm
> skeered to pull on 'em too hard.
>
> >
> > If you see the ten ohm load, again pull the fuses. Partially failed
> > recifiers in the alternator could be an unfused culprit, but I think all
the
> > electronics in today's vehicles are fused.
> >
> > What about the trailer light kit, is it aftermarket or oem? The
aftermarket
> > one I put on my Toyota would blow the fuse all by itself, when it felt
like
> > it.
> >
>
> OEM trailer wiring.
>
> > Happy hunting!
> >
>
> Thanks!
>
> --
> Charles
> '99 YZ250

Charles,

Used to be the light relay and the horn relay. Nowadays you got relays all
over the planet. I'd say if they have an obvious external holddowns, they
can be removed.

Don't overlook a starter bendix, although they would more likely be a full
short to ground.

Joe

XL600R - no starter bendix

"I found there's a 1.3A* load on the battery when the key is off. Doesn't
seem right, does it?"

Actually it does seem right. Modern vehicles can draw parasitic loads for
quite a while as various modules take time to "go to sleep". Some can take
up to a few hours depending on what conditions are present on the data bus,
such as who else is "awake" and what they're talking to each other about,
and when the conditions change such that they can stop talking. And as soon
as you open a door or do something else to wake one of them up, data traffic
starts again and can wake up others as well, starting the process all over
again.

Without a service manual to correctly diagnose parasitic load on modern
vehicles you're pretty well hosed. Things are much more complicated than
they used to be.

--
ADW
"HardWorkingDog" <harvey@mush.man> wrote in message
news:harvey-3B1BB8.22395826112007@individual.net...
> In article <figd3f$67o$1@aioe.org>,
> "Joseph Rooney" <ikerooneyat@pcmagic.net> wrote:
>
>> "HardWorkingDog" <harvey@mush.man> wrote in message
>> news:harvey-92E11B.21434826112007@individual.net...
>> > The YukonXL's (love that "XL" part) battery went dead a few days ago.
>> > In the process of diagnosing why, I found there's a 1.3A* load on the
>> > battery when the key is off. Doesn't seem right, does it?
>> >
>
>
>> >
>> > What could cause a current draw like this that doesn't go through a
>> > fuse or the ignition switch?
>> >
>
>>
>> I would approach it with an ohmmeter, that sounds like a ten ohm load on
>> the
>> battery. Measure from the disconnected positive battery lead and see if
>> you
>> see the ten ohm load. If not, it is some relay operated load, or maybe
>> the
>> On-Star system is ordering out.
>
> Thanks, but no On-Star. The black helicopters are quite enough.
>
> A relay-operated load, meaning, the relay is staying closed when power
> is off? Can I yank the relays off the panel just like a fuse? I'm
> skeered to pull on 'em too hard.
>
>>
>> If you see the ten ohm load, again pull the fuses. Partially failed
>> recifiers in the alternator could be an unfused culprit, but I think all
>> the
>> electronics in today's vehicles are fused.
>>
>> What about the trailer light kit, is it aftermarket or oem? The
>> aftermarket
>> one I put on my Toyota would blow the fuse all by itself, when it felt
>> like
>> it.
>>
>
> OEM trailer wiring.
>
>> Happy hunting!
>>
>
> Thanks!
>
> --
> Charles
> '99 YZ250

Andy Waddell says:

> "I found there's a 1.3A* load on the battery when the key is off. Doesn't
> seem right, does it?"
>
> Actually it does seem right.

1.3 Amps? Really? So a 220 amp-hour typical car battery will be
dead from parasitic draw in 7-ish days if you just leave it sit there?


Go fast. Take chances.
Mike S.

In article <Vfqdnb3_kJ-u7tHanZ2dnUVZ_hqdnZ2d@comcast.com>,
"Andy Waddell" <andywaddell@comcast.net> wrote:

> "I found there's a 1.3A* load on the battery when the key is off. Doesn't
> seem right, does it?"
>
> Actually it does seem right. Modern vehicles can draw parasitic loads for
> quite a while as various modules take time to "go to sleep". Some can take
> up to a few hours depending on what conditions are present on the data bus,
> such as who else is "awake" and what they're talking to each other about,
> and when the conditions change such that they can stop talking. And as soon
> as you open a door or do something else to wake one of them up, data traffic
> starts again and can wake up others as well, starting the process all over
> again.
>
> Without a service manual to correctly diagnose parasitic load on modern
> vehicles you're pretty well hosed. Things are much more complicated than
> they used to be.
>

Thanks Andy. I talked to my mechanic today (I figure I've paid for at
least 2 of his K1200's and a couple trips to Europe for him) and he
said I should wait at least a half-hour to check the current
drain...I'm heading over to alt.trucks.chevy

He also told me there's a few more fuses hidden beneath the main panel
under the hood.

I may also try disconnecting the alternator to see if a bad rectifier
may be responsible, as Joe suggested.

--
Charles
'99 YZ250

In article
<c8d549c0-7a64-4fe5-b845-f1d552e93d9e@j44g2000hsj.googlegroups.com>,
sturd <mikesturdevant127@hotmail.com> wrote:

> Andy Waddell says:
>
> > "I found there's a 1.3A* load on the battery when the key is off. Doesn't
> > seem right, does it?"
> >
> > Actually it does seem right.
>
> 1.3 Amps? Really? So a 220 amp-hour typical car battery will be
> dead from parasitic draw in 7-ish days if you just leave it sit there?
>
>

Well, that pretty much describes the symptoms I'm experiencing

--
Charles
'99 YZ250

On Nov 27, 7:36 pm, HardWorkingDog <har...@mush.man> wrote:
> In article <Vfqdnb3_kJ-u7tHanZ2dnUVZ_hqdn...@comcast.com>,
> "Andy Waddell" <andywadd...@comcast.net> wrote:
>
>
>
> > "I found there's a 1.3A* load on the battery when the key is off. Doesn't
> > seem right, does it?"
>
> > Actually it does seem right. Modern vehicles can draw parasitic loads for
> > quite a while as various modules take time to "go to sleep". Some can take
> > up to a few hours depending on what conditions are present on the data bus,
> > such as who else is "awake" and what they're talking to each other about,
> > and when the conditions change such that they can stop talking. And as soon
> > as you open a door or do something else to wake one of them up, data traffic
> > starts again and can wake up others as well, starting the process all over
> > again.
>
> > Without a service manual to correctly diagnose parasitic load on modern
> > vehicles you're pretty well hosed. Things are much more complicated than
> > they used to be.
>
> Thanks Andy. I talked to my mechanic today (I figure I've paid for at
> least 2 of his K1200's and a couple trips to Europe for him) and he
> said I should wait at least a half-hour to check the current
> drain...I'm heading over to alt.trucks.chevy
>
> He also told me there's a few more fuses hidden beneath the main panel
> under the hood.
>
> I may also try disconnecting the alternator to see if a bad rectifier
> may be responsible, as Joe suggested.
>
> --
> Charles
> '99 YZ250


In this emissions/mileage crazed world, maybe they keep the heat on
the O2 sensor, or the MAF, for a bit after its shut off.

Or maybe it uses the computer and a sensor to turn on the radiator fan
(if required) after shutdown, instead of a nice little snap switch.
Could be active for a bit after key-off.


DDave

boater types have solved this problem by installing an automatic battery
disconnect switch...
what they do is sense when the battery voltage drops below a level then it
disconnects the battery.... you know the type of person who parks blasts the
radio then falls asleep (passes out) then wakes up to a deed battery then
wants a jumpstart to get back to the bar.... well anyhow do a search for
auto disconnect battery marine or some such words and a few manufactures of
these cool things will pop up. they cost about 100 bucks (or two batteries)
and is sometimes much cheaper than reverse engineering a electronic
nightmare like previously submerged vehicles can be... DON'T ASK ME HOW I
KNOW...*(&^%$ spend better part of a year with twin Volvo induced insomnia
millimeter schematics spaghetti..<should have just stuck an auto disconnect
switch on it and be done>
john

"sturd" <mikesturdevant127@hotmail.com> wrote in message
news:c8d549c0-7a64-4fe5-b845-f1d552e93d9e@j44g2000hsj.googlegroups.com...
> Andy Waddell says:
>
>> "I found there's a 1.3A* load on the battery when the key is off. Doesn't
>> seem right, does it?"
>>
>> Actually it does seem right.
>
> 1.3 Amps? Really? So a 220 amp-hour typical car battery will be
> dead from parasitic draw in 7-ish days if you just leave it sit there?
>
>
> Go fast. Take chances.
> Mike S.