The BCM is always communicating with the ECU!

RK
"jim beam" <spamvortex@bad.example.net> wrote in message
news:SYqdnbM3Tqm7T6ranZ2dnUVZ_vninZ2d@speakeasy.ne t...
> Refinish King wrote:
>> On about 92 and up:
>>
>> The dome light is connected to the Body Control Module.
>
> yes, which is not the ecu!
>
>
>>
>> RK
>> "jim beam" <spamvortex@bad.example.net> wrote in message
>> news:VYadnT-dlqDY66ranZ2dnUVZ_qKgnZ2d@speakeasy.net...
>>> Tony Hwang wrote:
>>>> Gary L. Burnore wrote:
>>>>
>>>>> On Sun, 11 Nov 2007 02:17:38 GMT, Tony Hwang <dragon40@shaw.ca> wrote:
>>>>>
>>>>>
>>>>>> jim beam wrote:
>>>>>>
>>>>>>
>>>>>>> Hachiroku wrote:
>>>>>>> <snip crap>
>>>>>>>
>>>>>>>> I had heard of this before; I can't remember what the car was, but
>>>>>>>> someone
>>>>>>>> shorted out the ECU replacing the dome light...
>>>>>>>
>>>>>>> no way - the ecu's not even connected to the dome light. and
>>>>>>> they're electrically protected against all kinds of "user error",
>>>>>>> including battery reversal, over-voltage, dead shorts and static.
>>>>>>> short of direct lightning strike, water damage, or fire, none of
>>>>>>> which have a single damned thing to do with dome lights, the ecu's
>>>>>>> not going anywhere and it's /certainly/ not going to be fubared by a
>>>>>>> bulb change.
>>>>>> Hi,
>>>>>> No way? If short caused a surge in the electrical system,
>>>>>
>>>>> You're kidding right?
>>>> Hi,
>>>> Probably you don't even know basic Ohm's law or Kirchoff's or
>>>> Tevnin Norton's theorem, etc. If you want to debate, email me directly.
>>>> Let's compare our CV first.
>>> tony, this is usenet - "credentials" don't mean . just stick to the
>>> facts.
>>>
>>> fact 1 - batteries don't "surge". period. some [reactive] peripherals
>>> can do it, unless protected. in cars, they all are. dome lights are
>>> not reactive.
>>>
>>> fact 2 - ohmic behavior dictates that battery voltage drops as current
>>> increases, not the other way around.
>>>
>>> fact 3 - ecu's are "idiot proofed". per #1, a dome light has no
>>> reaction that could possibly cause a problem, even if the ecu was
>>> unprotected.
>>>
>>> conclusion: either address reality or move on.
>>

 

It could be a coincidence?

Maybe there is another problem.

RK
"Hachiroku ????" <Trueno@AE86.gts> wrote in message
news:wK7_i.1806$eV.1247@trndny04...
> On Sat, 10 Nov 2007 18:04:00 -0800, jim beam wrote:
>
>> Hachiroku wrote:
>> <snip crap>
>>> I had heard of this before; I can't remember what the car was, but
>>> someone shorted out the ECU replacing the dome light...
>>
>> no way - the ecu's not even connected to the dome light. and they're
>> electrically protected against all kinds of "user error", including
>> battery reversal, over-voltage, dead shorts and static. short of direct
>> lightning strike, water damage, or fire, none of which have a single
>> damned thing to do with dome lights, the ecu's not going anywhere and
>> it's
>> /certainly/ not going to be fubared by a bulb change.
>
> I talked to him last night. He says he wants you to come out and tell him
> why his Pathfinder won't start after changing the dome light...
>
>

 

On Tue, 13 Nov 2007 02:21:29 +0000, Scott in Florida wrote:

> On Tue, 13 Nov 2007 02:12:44 GMT, Hachiroku ???? <Trueno@AE86.gts> wrote:
>
>>On Sat, 10 Nov 2007 18:04:00 -0800, jim beam wrote:
>>
>>> Hachiroku wrote:
>>> <snip crap>
>>>> I had heard of this before; I can't remember what the car was, but
>>>> someone shorted out the ECU replacing the dome light...
>>>
>>> no way - the ecu's not even connected to the dome light. and they're
>>> electrically protected against all kinds of "user error", including
>>> battery reversal, over-voltage, dead shorts and static. short of
>>> direct lightning strike, water damage, or fire, none of which have a
>>> single damned thing to do with dome lights, the ecu's not going
>>> anywhere and it's /certainly/ not going to be fubared by a bulb change.
>>
>>I talked to him last night. He says he wants you to come out and tell him
>>why his Pathfinder won't start after changing the dome light...
>>
>>
> Anybody that says a short on a voltage line can't hurt an ECU has never
> worked on computers.....


He said there was a spark when he tried to remove the bulb. The bulb's
glass was broken, and he tried to grab it without touching anything else,
but there was a spark, and when he tried to start the truck...nothing.

He had it towed to a Nissan dealer. They're trying to find a used ECU and
told him that before doing ANYTHING electrical with the truck he should...

disconnect the negative battery terminal...

(Next week he's removing the terminal and installing a Negative Terminal
Shut-off...)

 

On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
> > tony, this is usenet - "credentials" don't mean . just stick to the
> > facts.
>
> > fact 1 - batteries don't "surge". period. some [reactive] peripherals
> > can do it, unless protected. in cars, they all are. dome lights are
> > not reactive.
>
> No but a direct short could cause a problem in the item shorted. In the
> case of some vehicles that could be the BCM if they use it for things
> like an interior light timer/dimmer (close door and dome light stays on
> for a bit) Shorting that circuit cause problems.
>
>
>
> > fact 2 - ohmic behavior dictates that battery voltage drops as current
> > increases, not the other way around.
>
> Yes BUT take a chunk of wire and toss it across the battery. Measure the
> battery voltage. It likely won't cause a voltage drop as it heats up and
> melts.
>
>
>
> > fact 3 - ecu's are "idiot proofed". per #1, a dome light has no
> > reaction that could possibly cause a problem, even if the ecu was
> > unprotected.
>
> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
> SOP in the body shop is to pull the ECU on anything that rolls in for
> panel work. One good zap from a welder can kill the ECU without being
> near it.
>
>
>
> > conclusion: either address reality or move on.
>
> --
> Steve W.
> Near Cooperstown, New York
> NRA Member
> Pacifism - The theory that if they'd fed
> Jeffrey Dahmer enough human flesh,
> he'd have become a vegan.

Guys, guys... go get a schematic and find out if the dome light is in
the same circut as the ECU. Even if it is, I don't think the changing
of the bulb is what caused the problem. I do think that whatever
caused the light to function intermittantly MIGHT have cused the ECU
problem. Either way, if the light was working sometimes, that would
tell me that there was nothing wrong with the bulb. Funny thing about
light bulbs... they either work, or they don't. The filament is either
complete, or it's not. It doesn't go back once it's blown. Okay, so if
there's a short, it would be either in the fixture, or in the wires
going to it. Furthermore, That's what fuses are for! I've done it many
many times. Shorting things out and blowing fuses and replacing them
again. The fuse opens the circut in the event of a short before
ANYTHING gets damaged (unless the fuse is either disregarded, or
replaced with a fuse of a higher amperage). And furthermore, since
we're on the topic of fuses, this is the whole reason that things like
dome lights and tail lights and headlights and radios and ESPECIALLY
ECU's are all on thier own circuts with thier own fuses. Kind of
insurance, if one thing blows a fuse, you don't lose everything at
once. I do agree with the titlehead of this issue, being "disconnect
the negitive before working". But this rule is mostly in place because
sometimes people like to play with the wires and accidently drop the
exposed end of a hot wire onto the bare frame of body of the vehicle.
The result can be a blown fuse at minimum, or a small fire at most
(I've been there, too). However, I regress (and conclude), the dome
light bulb cannot be the reason for ECU problems. ECU's may or may not
be "idiot proofed," but they are not on the same circut as the dome
light, the dome light cannot cause "power surges" and niether can
anything else on a vehicle, and even if anything were to happen, the
fuses would have caught it. Case Closed. Go get a new ECU, and re-wire
your dome light. quit griping about crap that is not relevant. The
more you gripe, the more other people despise you, and the job still
is not done.

 

On Tue, 13 Nov 2007 04:33:54 +0000, fury45iii wrote:

> Guys, guys... go get a schematic and find out if the dome light is in the
> same circut as the ECU. Even if it is, I don't think the changing of the
> bulb is what caused the problem. I do think that whatever caused the light
> to function intermittantly MIGHT have cused the ECU problem. Either way,
> if the light was working sometimes, that would tell me that there was
> nothing wrong with the bulb. Funny thing about light bulbs... they either
> work, or they don't. The filament is either complete, or it's not. It
> doesn't go back once it's blown. Okay, so if there's a short, it would be
> either in the fixture, or in the wires going to it. Furthermore, That's
> what fuses are for! I've done it many many times. Shorting things out and
> blowing fuses and replacing them again.


Yeah, but we're talking a Nissan here! I've seenthings in Nissans I've
never seen in other cars.

And, he said the glass was broken. How it even lit without burning out is
a mystery!

 

On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:

> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
> SOP in the body shop is to pull the ECU on anything that rolls in for
> panel work. One good zap from a welder can kill the ECU without being
> near it.

A welder and a dome light are vastly different things. An arc
welder generates a HUGE reactive voltage spike when striking the arc,
and that spike can wander all over the entire vehicle and fry
sensitive electronics and not-so-sensitive things, too, like
alternator diodes. Standard procedure there is to disconnect the
battery whenever doing any welding on the thing. Shorting a dome light
will NOT generate any sort of spike. Period. You need a coil to
generate spikes, coils like those found in starters, alternator
rotors, ignition coils. You might as well try to generate a spike by
disconecting and reconnecting the battery.

Dan

 

Dan_Thomas_nospam@yahoo.com wrote:

> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>
>
>>VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>SOP in the body shop is to pull the ECU on anything that rolls in for
>>panel work. One good zap from a welder can kill the ECU without being
>>near it.
>
>
> A welder and a dome light are vastly different things. An arc
> welder generates a HUGE reactive voltage spike when striking the arc,
> and that spike can wander all over the entire vehicle and fry
> sensitive electronics and not-so-sensitive things, too, like
> alternator diodes. Standard procedure there is to disconnect the
> battery whenever doing any welding on the thing. Shorting a dome light
> will NOT generate any sort of spike. Period. You need a coil to
> generate spikes, coils like those found in starters, alternator
> rotors, ignition coils. You might as well try to generate a spike by
> disconecting and reconnecting the battery.
>
> Dan
>
Hmmm,
Lamp filament is a tiny coil, LOL!

 

Tony Hwang wrote:
> Dan_Thomas_nospam@yahoo.com wrote:
>
>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>
>>
>>> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>> SOP in the body shop is to pull the ECU on anything that rolls in for
>>> panel work. One good zap from a welder can kill the ECU without being
>>> near it.
>>
>>
>> A welder and a dome light are vastly different things. An arc
>> welder generates a HUGE reactive voltage spike when striking the arc,
>> and that spike can wander all over the entire vehicle and fry
>> sensitive electronics and not-so-sensitive things, too, like
>> alternator diodes. Standard procedure there is to disconnect the
>> battery whenever doing any welding on the thing. Shorting a dome light
>> will NOT generate any sort of spike. Period. You need a coil to
>> generate spikes, coils like those found in starters, alternator
>> rotors, ignition coils. You might as well try to generate a spike by
>> disconecting and reconnecting the battery.
>>
>> Dan
>>
> Hmmm,
> Lamp filament is a tiny coil, LOL!

with an air core and virtually no inductance. if you have instruments
that can measure any voltage spike you get from a coiled bulb filament,
i'd love to see your readings.

 

jim beam wrote:

> Tony Hwang wrote:
>
>> Dan_Thomas_nospam@yahoo.com wrote:
>>
>>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>>
>>>
>>>> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>>> SOP in the body shop is to pull the ECU on anything that rolls in for
>>>> panel work. One good zap from a welder can kill the ECU without being
>>>> near it.
>>>
>>>
>>>
>>> A welder and a dome light are vastly different things. An arc
>>> welder generates a HUGE reactive voltage spike when striking the arc,
>>> and that spike can wander all over the entire vehicle and fry
>>> sensitive electronics and not-so-sensitive things, too, like
>>> alternator diodes. Standard procedure there is to disconnect the
>>> battery whenever doing any welding on the thing. Shorting a dome light
>>> will NOT generate any sort of spike. Period. You need a coil to
>>> generate spikes, coils like those found in starters, alternator
>>> rotors, ignition coils. You might as well try to generate a spike by
>>> disconecting and reconnecting the battery.
>>>
>>> Dan
>>>
>> Hmmm,
>> Lamp filament is a tiny coil, LOL!
>
>
> with an air core and virtually no inductance. if you have instruments
> that can measure any voltage spike you get from a coiled bulb filament,
> i'd love to see your readings.
Hmmm,
You are so bone headed, can't even take a joke.
The more you babble, the more you reveal your lack of knowledge:
pratical or thory. My job used to deal with fraction of nano amps. VLSI,
ASIC, etc. on mil-spec.

 

Tony Hwang wrote:
> jim beam wrote:
>
>> Tony Hwang wrote:
>>
>>> Dan_Thomas_nospam@yahoo.com wrote:
>>>
>>>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>>>
>>>>
>>>>> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>>>> SOP in the body shop is to pull the ECU on anything that rolls in for
>>>>> panel work. One good zap from a welder can kill the ECU without being
>>>>> near it.
>>>>
>>>>
>>>>
>>>> A welder and a dome light are vastly different things. An arc
>>>> welder generates a HUGE reactive voltage spike when striking the arc,
>>>> and that spike can wander all over the entire vehicle and fry
>>>> sensitive electronics and not-so-sensitive things, too, like
>>>> alternator diodes. Standard procedure there is to disconnect the
>>>> battery whenever doing any welding on the thing. Shorting a dome light
>>>> will NOT generate any sort of spike. Period. You need a coil to
>>>> generate spikes, coils like those found in starters, alternator
>>>> rotors, ignition coils. You might as well try to generate a spike by
>>>> disconecting and reconnecting the battery.
>>>>
>>>> Dan
>>>>
>>> Hmmm,
>>> Lamp filament is a tiny coil, LOL!
>>
>>
>> with an air core and virtually no inductance. if you have instruments
>> that can measure any voltage spike you get from a coiled bulb
>> filament, i'd love to see your readings.
> Hmmm,
> You are so bone headed, can't even take a joke.
> The more you babble, the more you reveal your lack of knowledge:
> pratical or thory. My job used to deal with fraction of nano amps. VLSI,
> ASIC, etc. on mil-spec.

bullshitting idiot.

 

jim beam <spamvortex@bad.example.net> wrote:
>with an air core and virtually no inductance. if you have instruments
>that can measure any voltage spike you get from a coiled bulb filament,
>i'd love to see your readings.

I do.

BUT, you don't need one. If you have an 1141 lamp with 50 loops of
1/16" (that's estimated by eye here) about 1/2" long, you can use
Wheeler's Formula:

50^2 * (0.065)^2 10.5
--------------- = ----- = 0.27 microhenries
18 * 0.065 + 40 * 0.5 28.0


That's a lot less than the hundreds of henries that an arc welder ballast
will have, and it's probably small enough to be compensated for by the
capacitance of the wiring, even. But it's enough that you could measure it
carefully with a scope and a pulse generator, even though it's actually
going to be swamped at any reasonable voltage by the nonlinearity when the
filament heats up and its resistance increases.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

I personally have seen a bunch of blown ECU's caused by wiring shorts,
mostly fuel pumps, but other things too.

Sure the ECU is 'protected' by a diode, but no one sells the damn diode
to replace the blown one nor do many 'authorized' places exist to fix
them. Half are sunk in a block of plastic also.

I have repaired a few by using a cheap diode with a +/- 10 to 15%
tolerance so they fell close to the original specs. Close enough to work.

If the dome light is on a timer, it is connected to some kind of
computer....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08

Hachiroku ハチãƒã‚¯ wrote:
> I was lokking thorugh the Subaru manual to find out where the thermostat
> was. I'm used to it being on TOP of the engine.
>
> While it ididn't show the location, it did say, "Remove negative battery
> terminal, and remove thermostat housing..."
>
> Huh? Remove the - terminal berfore removing the thermostat housing?! WTF?!?!
>
> Last night I went to pick up my papers for my "paper route" and saw a
> big-*** GMC pickup I hadn't seen before. Then I saw one of my firend's
> fathers, who started doing the papers about 10 days after I did. He
> usually drive an '01 Pathfinder.
>
> "Where's the Pathfinder?" "I wrecked it." "WHAT?!?!?!?!"
>
> Well, he didn't really wreck it. He had a bad bulb in the overhead light.
> He removed the lens, and the bulb was in pieces, but still working
> intermittantly. He removed the bulb and replaced the lens, and then tried
> to start the truck. No Go. The starter spins, but the engine doesn't catch.
>
> Looks like he fried the ECU!!!! All the other lights work, the dome light
> works, but the fuel pumpo doesn't energize. He tried the reset procedure
> and nothing.
>
> I had heard of this before; I can't remember what the car was, but someone
> shorted out the ECU replacing the dome light...
>
>

 

"Hachiroku ????" <Trueno@AE86.gts> wrote in message
news:lzt_i.7967$ds.6186@trndny09...
> On Tue, 13 Nov 2007 04:33:54 +0000, fury45iii wrote:
>
>> Guys, guys... go get a schematic and find out if the dome light is in the
>> same circut as the ECU. Even if it is, I don't think the changing of the
>> bulb is what caused the problem. I do think that whatever caused the
>> light
>> to function intermittantly MIGHT have cused the ECU problem. Either way,
>> if the light was working sometimes, that would tell me that there was
>> nothing wrong with the bulb. Funny thing about light bulbs... they either
>> work, or they don't. The filament is either complete, or it's not. It
>> doesn't go back once it's blown. Okay, so if there's a short, it would be
>> either in the fixture, or in the wires going to it. Furthermore, That's
>> what fuses are for! I've done it many many times. Shorting things out and
>> blowing fuses and replacing them again.
>
>
> Yeah, but we're talking a Nissan here! I've seenthings in Nissans I've
> never seen in other cars.
>
> And, he said the glass was broken. How it even lit without burning out is
> a mystery!
>
>

First you said that the bulb was in pieces, not that the glass was broken.
Was it really broken?
I have seen several times that the glass part of a bulb can separate from
its socket but still hanging by the leads it may still work.
And I have also seen that the ends of a broken lamp filament can dangle
together and get get kind of welded together, so it works again, but usually
not for long.
What may kill an ECU is the very very short transients in voltage when a
cirquit somewhere in the system is abruptly opened or closed, especially
when it is high current (a short) and/or repeated many times. If he made a
momentarily short cirquit while changing the bulb that MAY be enough.
That is why with modern cars we are advised not to use jumper cables without
transient suppressors.

Asbjørn

 

Hello:

This might seem odd to you but, newer cars use bulbs that are a specific
impedance. A 2157 is the same candle power as an 1157, but the impedance is
higher. That's why if you use a 2157 in place of a 3057 for argument's sake.

You'll get a check engine light in an OBD2 compliant vehicle.

RK
"Tony Hwang" <dragon40@shaw.ca> wrote in message
news:zou_i.208792$th2.154494@pd7urf3no...
> Dan_Thomas_nospam@yahoo.com wrote:
>
>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>
>>
>>>VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>>SOP in the body shop is to pull the ECU on anything that rolls in for
>>>panel work. One good zap from a welder can kill the ECU without being
>>>near it.
>>
>>
>> A welder and a dome light are vastly different things. An arc
>> welder generates a HUGE reactive voltage spike when striking the arc,
>> and that spike can wander all over the entire vehicle and fry
>> sensitive electronics and not-so-sensitive things, too, like
>> alternator diodes. Standard procedure there is to disconnect the
>> battery whenever doing any welding on the thing. Shorting a dome light
>> will NOT generate any sort of spike. Period. You need a coil to
>> generate spikes, coils like those found in starters, alternator
>> rotors, ignition coils. You might as well try to generate a spike by
>> disconecting and reconnecting the battery.
>>
>> Dan
>>
> Hmmm,
> Lamp filament is a tiny coil, LOL!

 

The very reason that using a wrong bulb:

Will set a code on an OBD2 system.

RK

PS
I'm not speculating on Jim's method of earning a living. But there are such
instruments available.
"jim beam" <spamvortex@bad.example.net> wrote in message
news:eK-dnSP_xrPhEqfanZ2dnUVZ_qHinZ2d@speakeasy.net...
> Tony Hwang wrote:
>> jim beam wrote:
>>
>>> Tony Hwang wrote:
>>>
>>>> Dan_Thomas_nospam@yahoo.com wrote:
>>>>
>>>>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>>>>
>>>>>
>>>>>> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>>>>> SOP in the body shop is to pull the ECU on anything that rolls in for
>>>>>> panel work. One good zap from a welder can kill the ECU without being
>>>>>> near it.
>>>>>
>>>>>
>>>>>
>>>>> A welder and a dome light are vastly different things. An arc
>>>>> welder generates a HUGE reactive voltage spike when striking the arc,
>>>>> and that spike can wander all over the entire vehicle and fry
>>>>> sensitive electronics and not-so-sensitive things, too, like
>>>>> alternator diodes. Standard procedure there is to disconnect the
>>>>> battery whenever doing any welding on the thing. Shorting a dome light
>>>>> will NOT generate any sort of spike. Period. You need a coil to
>>>>> generate spikes, coils like those found in starters, alternator
>>>>> rotors, ignition coils. You might as well try to generate a spike by
>>>>> disconecting and reconnecting the battery.
>>>>>
>>>>> Dan
>>>>>
>>>> Hmmm,
>>>> Lamp filament is a tiny coil, LOL!
>>>
>>>
>>> with an air core and virtually no inductance. if you have instruments
>>> that can measure any voltage spike you get from a coiled bulb filament,
>>> i'd love to see your readings.
>> Hmmm,
>> You are so bone headed, can't even take a joke.
>> The more you babble, the more you reveal your lack of knowledge:
>> pratical or thory. My job used to deal with fraction of nano amps. VLSI,
>> ASIC, etc. on mil-spec.
>
> bullshitting idiot.