The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but
first, as it's Canbus they hook their computer to the car, tell the
cars computer they have replaced the bulb, and then the brake light
starts working. Very odd (and none of us have enough knowledge of how
the system works to be able to explain it. Maybe it just had a brain
fart?)
--
Chris French

Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the system
works to be able to explain it. Maybe it just had a brain fart?)

I'm afraid this kind of chicanery is all too common nowadays. Believe it or
not, this is probably how it's meant to work.

Makes a bit of a nonsense of rules in some countries that insist that you
carry spare bulbs. Roadside repairs are fast becoming a thing of the past.

Tim

On 15/01/2015 22:35, Tim+ wrote:
....
Makes a bit of a nonsense of rules in some countries that insist that you
carry spare bulbs. ...

Are there any that still require this? It hasn't been required in France
for some years now.


--
Colin Bignell

In message
-septemb
er.org, Tim+ writes
Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the system
works to be able to explain it. Maybe it just had a brain fart?)

I'm afraid this kind of chicanery is all too common nowadays. Believe it or
not, this is probably how it's meant to work.

No, I don't believe so, my garage had not come across it before (not a
ford specialist, but they have always been very good). They rang the
nearby large Ford dealers and they didn't suggest it. From what one chap
there said I think the garage even goggled it up and that didn't seem to
turn up much - just some suggestions of replacing the wiring loom for
similar faults.

It's a common car, if it was normal behaviour it would be documented.

and I've changed other bulbs on the car with no problem, why would they
do it for one bulb?



Makes a bit of a nonsense of rules in some countries that insist that you
carry spare bulbs.

Not really, since this just seems to have been a bit of an oddity
(software bug? weird blip in the system, who knows)

--
Chris French

"Chris French" wrote in message
...
In message
-septemb
er.org, Tim+ writes
Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but
first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the
system
works to be able to explain it. Maybe it just had a brain fart?)

I'm afraid this kind of chicanery is all too common nowadays. Believe it
or
not, this is probably how it's meant to work.

No, I don't believe so, my garage had not come across it before (not a
ford specialist, but they have always been very good). They rang the
nearby large Ford dealers and they didn't suggest it. From what one chap
there said I think the garage even goggled it up and that didn't seem to
turn up much - just some suggestions of replacing the wiring loom for
similar faults.

It's a common car, if it was normal behaviour it would be documented.

and I've changed other bulbs on the car with no problem, why would they do
it for one bulb?

Maybe this one failed with the bulb shorting as the filament
came off and bulbs don't usually fail that way, so you don't
usually see the software noticing that sort of short and not
powering that line until its told that the bulb has been replaced.

Maybe more of a documentation failure than anything else.



Makes a bit of a nonsense of rules in some countries that insist that you
carry spare bulbs.

Not really, since this just seems to have been a bit of an oddity
(software bug? weird blip in the system, who knows)

On 15/01/2015 20:09, Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but
first, as it's Canbus they hook their computer to the car, tell the
cars computer they have replaced the bulb, and then the brake light
starts working. Very odd (and none of us have enough knowledge of how
the system works to be able to explain it. Maybe it just had a brain fart?)

My Leon has CANBUS, and I recently had a brake/tail lamp failure (it's a
single filament 21W bulb that they dim with PWM for a tail lamp).
Changed it, no good, but turning off the ignition and/or lights made it
work. I think once the controller detects a failed bulb, it disables it
until next start.

On 16/01/2015 00:41, Chris French wrote:
In message
-septemb
er.org, Tim+ writes
Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but
first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the
system
works to be able to explain it. Maybe it just had a brain fart?)

I'm afraid this kind of chicanery is all too common nowadays. Believe
it or
not, this is probably how it's meant to work.

No, I don't believe so, my garage had not come across it before (not a
ford specialist, but they have always been very good). They rang the
nearby large Ford dealers and they didn't suggest it. From what one chap
there said I think the garage even goggled it up and that didn't seem to
turn up much - just some suggestions of replacing the wiring loom for
similar faults.

It's a common car, if it was normal behaviour it would be documented.

and I've changed other bulbs on the car with no problem, why would they
do it for one bulb?



Makes a bit of a nonsense of rules in some countries that insist that you
carry spare bulbs.

Not really, since this just seems to have been a bit of an oddity
(software bug? weird blip in the system, who knows)

I think it is deliberate, possibly to protect the CE module from a
shorted output.

It might be that they are separate and it blew short circuit so the brain
disconnected it. after all if there is a facility to tell it you changed it
that has to be there for a reason.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Chris French" wrote in message
...
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power, check
for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the system
works to be able to explain it. Maybe it just had a brain fart?)
--
Chris French

"Chris French" wrote in message
...
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power, check
for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the system
works to be able to explain it. Maybe it just had a brain fart?)

Probably a wire broken inside the insulation giving an intermittant
connection.
As you say the likely place is where the cables is bent to and fro at the
door hinge.
Hard to find.
You can follow the electricty by stripping back the insulation here and
there.
However you need a wiring diagram that shows cable colours really.

On 16/01/15 07:49, Chris Bartram wrote:

My Leon has CANBUS, and I recently had a brake/tail lamp failure (it's a
single filament 21W bulb that they dim with PWM for a tail lamp).
Changed it, no good, but turning off the ignition and/or lights made it
work. I think once the controller detects a failed bulb, it disables it
until next start.

My VW Touran has CANBUS - when I got an after market radio fitted, I
enquired whether it was best to use a CANBUS interface module or just to
hack it into an ignition fed handy wire in the old tried and tested way.

The answer was: the latter. The fitters did have all the OBD-II and
VAGCOM/CANBUS kit, but they said that on VWs of my vintage at least,
they were likely to end up having to upgrade the firmware in a number of
random computers around the car to make the adaptor module play nice.

They could have been lying, but given they actually sold the adaptor and
had good reviews, I see no reason to assume so.

It sounded a complete mess - so I opted for plan B and it's worked out
fine (the handy ignition fed cable is a big fat one to the aircon switch
right next to the radio bay)

On 16/01/2015 09:24, Tim Watts wrote:
On 16/01/15 07:49, Chris Bartram wrote:

My Leon has CANBUS, and I recently had a brake/tail lamp failure (it's a
single filament 21W bulb that they dim with PWM for a tail lamp).
Changed it, no good, but turning off the ignition and/or lights made it
work. I think once the controller detects a failed bulb, it disables it
until next start.

My VW Touran has CANBUS - when I got an after market radio fitted, I
enquired whether it was best to use a CANBUS interface module or just to
hack it into an ignition fed handy wire in the old tried and tested way.

The answer was: the latter. The fitters did have all the OBD-II and
VAGCOM/CANBUS kit, but they said that on VWs of my vintage at least,
they were likely to end up having to upgrade the firmware in a number of
random computers around the car to make the adaptor module play nice.

They could have been lying, but given they actually sold the adaptor and
had good reviews, I see no reason to assume so.

It sounded a complete mess - so I opted for plan B and it's worked out
fine (the handy ignition fed cable is a big fat one to the aircon switch
right next to the radio bay)

I do know that for many VAG cars of that era, an aftermarket radio can
drain the battery if you don't upgrade the CAN gateway.

On 16/01/2015 08:36, Brian Gaff wrote:
It might be that they are separate and it blew short circuit so the brain
disconnected it. after all if there is a facility to tell it you changed it
that has to be there for a reason.
Brian

There isn't actually a facility to say you changed it, just the facility
to clear the error from the controller.

On Fri, 16 Jan 2015 00:41:06 +0000
Chris French wrote:

In message
-septemb
er.org, Tim+ writes
Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the
light unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no
power, check for broken wire where it goes from tailgate to car
body - ok.

Looking at having to track the cables through the wiring loom, but
first, as it's Canbus they hook their computer to the car, tell
the cars computer they have replaced the bulb, and then the brake
light starts working. Very odd (and none of us have enough
knowledge of how the system works to be able to explain it. Maybe
it just had a brain fart?)

I'm afraid this kind of chicanery is all too common nowadays.
Believe it or not, this is probably how it's meant to work.

No, I don't believe so, my garage had not come across it before (not
a ford specialist, but they have always been very good). They rang
the nearby large Ford dealers and they didn't suggest it. From what
one chap there said I think the garage even goggled it up and that
didn't seem to turn up much - just some suggestions of replacing the
wiring loom for similar faults.

It's a common car, if it was normal behaviour it would be documented.

and I've changed other bulbs on the car with no problem, why would
they do it for one bulb?



Makes a bit of a nonsense of rules in some countries that insist
that you carry spare bulbs.

Not really, since this just seems to have been a bit of an oddity
(software bug? weird blip in the system, who knows)


My Renault Laguna recently told me that one of the rear license plate
lamps had failed. I replaced it with a new one, but it didn't come on,
then switched bulbs, which proved that the new bulb was good, but still
only had the same location lit up, and then switched them back, and
everything worked fine. At no time during this did I start the engine,
just turned the light switch on and off each time.
They just have minds of their own, they don't work the way we expect!

--
Davey.

In message , john james
writes


"Chris French" wrote in message
...
In message
-septemb
er.org, Tim+ writes
Chris French wrote:
The high level brake light on our 2009 Ford Galaxy wasn't working,
replaced bulb, still not working. Didn't seem to be power to the light
unit. Thought I'd leave it to the garage to faff about with.

Few weeks later it goes in for it's MOT, they investigate, no power,
check for broken wire where it goes from tailgate to car body - ok.

Looking at having to track the cables through the wiring loom, but
first,
as it's Canbus they hook their computer to the car, tell the cars
computer they have replaced the bulb, and then the brake light starts
working. Very odd (and none of us have enough knowledge of how the
system
works to be able to explain it. Maybe it just had a brain fart?)

I'm afraid this kind of chicanery is all too common nowadays. Believe
it or
not, this is probably how it's meant to work.

No, I don't believe so, my garage had not come across it before (not
a ford specialist, but they have always been very good). They rang
the nearby large Ford dealers and they didn't suggest it. From what
one chap there said I think the garage even goggled it up and that
didn't seem to turn up much - just some suggestions of replacing the
wiring loom for similar faults.

It's a common car, if it was normal behaviour it would be documented.

and I've changed other bulbs on the car with no problem, why would
they do it for one bulb?

Maybe this one failed with the bulb shorting as the filament
came off and bulbs don't usually fail that way, so you don't
usually see the software noticing that sort of short and not
powering that line until its told that the bulb has been replaced.

Maybe more of a documentation failure than anything else.


Could be I guess, though still a bit surprised that it's not common
enough (even though not a usual bulb failure mode) to be known about as
a possibility.

I'll have to suggest it to the garage next time I'm in
--
Chris French