Back in the dark ages I had a Rover 214 with a tow bar. But it didnt have
an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an extra
bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact, and
only when the extra bulb was connected would the current be sufficient to
throw the switch?

Or something else?


--
Chris

On 18/04/2021 11:38, Chris Holmes wrote:


Back in the dark ages I had a Rover 214 with a tow bar. But it didnt have
an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an extra
bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact, and
only when the extra bulb was connected would the current be sufficient to
throw the switch?

Or something else?


I don't know but mine has the same thing except it sounds a buzzer.

Bill

Chris Holmes explained :
How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact, and
only when the extra bulb was connected would the current be sufficient to
throw the switch?

Yes, through a relay with a low resistance coil winding.

They used the same idea for detecting when a car lamp failed long ago.
It's all done by electronics now.

In article ,
Chris Holmes wrote:


Back in the dark ages I had a Rover 214 with a tow bar. But it didn‘t
have an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an
extra bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact,
and only when the extra bulb was connected would the current be
sufficient to throw the switch?

Or something else?

You need an indicator light to tell you you have a trailer attached?


--

--
*If all is not lost, where the hell is it?

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

After serious thinking williamwright wrote :
I don't know but mine has the same thing except it sounds a buzzer.

My fancy system indicates nothing at all if everything is working
properly - I'm not sure it is entirely legal to the letter of the law.

Rather it monitors all of the trailer lighting constantly and puts an
icon up on the screen, indicating which bulb has failed. Once on, it
stays on screen, until the engine is restarted - so no chance of it
missing an intermitant problem.

In article ,
Harry Bloomfield wrote:
Chris Holmes explained :
How would this have worked? Would all of the indicator current have
been sent through the coil that activated the switch for the extra
contact, and only when the extra bulb was connected would the current
be sufficient to throw the switch?

Yes, through a relay with a low resistance coil winding.

They used the same idea for detecting when a car lamp failed long ago.
It's all done by electronics now.

The bulb failure unit on the old Rover uses reed relays. And a vast amount
of extra cabling.

--
*If you must choose between two evils, pick the one you've never tried before

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

Dave Plowman (News) was thinking very hard :
The bulb failure unit on the old Rover uses reed relays. And a vast amount
of extra cabling.

No extra wiring in mine - all done digimagically.

On 18/04/2021 14:34, Dave Plowman (News) wrote:
In article ,
Chris Holmes wrote:


Back in the dark ages I had a Rover 214 with a tow bar. But it didn€˜t
have an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an
extra bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact,
and only when the extra bulb was connected would the current be
sufficient to throw the switch?

Or something else?

You need an indicator light to tell you you have a trailer attached?

There is a legal requirement to indicate whether or not the trailer
indicators are working.

It used to be done with an extra dash-light, later and more simply with
a buzzer in the boot (where all the wiring was) and these days, the
car's electronics usually cope with it - either by a similar check or by
a short pulse every few seconds to prove that all the trailer lights are
working (and incidentally, by showing that the trailer is there,
modifying the operation of the braking and stability programs.

So what is this supposed to do? If its just so direction and hazard
indicators on the trailer work, normally these seem to be part of the
standard connection and run in parallel with the cars ones just like all the
other lights do. However if its an indication only that a trailer is hooked
up that would be easy to achieve with a link in the plug when its attached.
Some car stuff seems to be unreasonably complicated for what its supposed to
do..
Brian

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"Chris Holmes" wrote in message
...


Back in the dark ages I had a Rover 214 with a tow bar. But it didn't have
an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an
extra
bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact, and
only when the extra bulb was connected would the current be sufficient to
throw the switch?

Or something else?


--
Chris

That could be done by a chip called a window comparator, witch is capable of
monitoring the current or resistance depending on how its set up, of each
light, but do people really go to this complexity these days?
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
Harry Bloomfield; "Esq." wrote in message
...
After serious thinking williamwright wrote :
I don't know but mine has the same thing except it sounds a buzzer.

My fancy system indicates nothing at all if everything is working
properly - I'm not sure it is entirely legal to the letter of the law.

Rather it monitors all of the trailer lighting constantly and puts an icon
up on the screen, indicating which bulb has failed. Once on, it stays on
screen, until the engine is restarted - so no chance of it missing an
intermitant problem.

Brian Gaff (Sofa) explained on 19/04/2021 :
That could be done by a chip called a window comparator, witch is capable of
monitoring the current or resistance depending on how its set up, of each
light, but do people really go to this complexity these days?

Obviously they do, or I would not have one. It is the OEM BMW optional
CAN-BUS part. My car already has/had a full road lighting monitoring
system It cost me around £130 extra for the extra towing module,
compared to the basic towing adaptor sold by the accessory shops. A
single extra wire relays data back to the lighting control module in
the dash. Worth it to know my lighting is fully working on my trailer.

Brian Gaff (Sofa) was thinking very hard :
So what is this supposed to do? If its just so direction and hazard
indicators on the trailer work, normally these seem to be part of the
standard connection and run in parallel with the cars ones just like all the
other lights do. However if its an indication only that a trailer is hooked
up that would be easy to achieve with a link in the plug when its attached.

No, they are supposed to monitor the current, to provide feedback that
the trailer indicator is actually drawing some current/ working. No
buzzer/WL flashing = cable fault or lamp failed.

Brian Gaff (Sofa) wrote

So what is this supposed to do?

Tell you if the trailer indicators arent working.

If its just so direction and hazard indicators on the trailer work,
normally these seem to be part of the standard connection and run in
parallel with the cars ones just like all the other lights do.

However if its an indication only that a trailer is hooked up

Nope.

that would be easy to achieve with a link in the plug when its attached.

Some car stuff seems to be unreasonably complicated for what its supposed
to do..


"Chris Holmes" wrote in message
...


Back in the dark ages I had a Rover 214 with a tow bar. But it didn't
have
an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an
extra
bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact,
and
only when the extra bulb was connected would the current be sufficient to
throw the switch?

Or something else?


--
Chris

Brian Gaff (Sofa) wrote

That could be done by a chip called a window comparator, witch is capable
of monitoring the current or resistance depending on how its set up, of
each light, but do people really go to this complexity these days?

Nope, these days the system can work out if any bulb has failed.

Harry Bloomfield; "Esq." wrote in message
...
After serious thinking williamwright wrote :
I don't know but mine has the same thing except it sounds a buzzer.

My fancy system indicates nothing at all if everything is working
properly - I'm not sure it is entirely legal to the letter of the law.

Rather it monitors all of the trailer lighting constantly and puts an
icon up on the screen, indicating which bulb has failed. Once on, it
stays on screen, until the engine is restarted - so no chance of it
missing an intermitant problem.

On Mon, 19 Apr 2021 19:04:51 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Nope

LOL! Senile ****head!

--
Keema Nam addressing nym-shifting senile Rodent:
"You are now exposed as a liar, as well as an ignorant troll."
"MID: .com"

On Mon, 19 Apr 2021 19:03:32 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Nope.

You ARE bat**** crazy, you abnormal trolling senile pest!

--
Kerr-Mudd,John addressing the auto-contradicting senile cretin:
"Auto-contradictor Rod is back! (in the KF)"
MID:

In article , Chris Holmes
writes


Back in the dark ages I had a Rover 214 with a tow bar. But it didnt have
an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an extra
bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact, and
only when the extra bulb was connected would the current be sufficient to
throw the switch?

Or something else?


My Defender still has that and it is much better than the faintly
audible though not if passengers were talking system which replaced it.
--
bert

In article , "Dave Plowman (News)"
writes
In article ,
Chris Holmes wrote:


Back in the dark ages I had a Rover 214 with a tow bar. But it didn€˜t
have an indicator to show when you had a trailer attached.

It was possible to buy a replacement indicator relay which had an extra
output to light a bulb on the dash when it detected that there was an
extra bulb in parallel with the indicators.

How would this have worked? Would all of the indicator current have been
sent through the coil that activated the switch for the extra contact,
and only when the extra bulb was connected would the current be
sufficient to throw the switch?

Or something else?

You need an indicator light to tell you you have a trailer attached?


--

Last time I looked, which was some time ago you were required to have an
indication that your trailer indicators were working. Originally that
was visible and still is on my Defender but then switched to audible, to
save the manufacturers putting in a cable and dash light which in most
cars was never used. Don't know what it is now but on my 2015 T5
Transporter it is still audible.
--
bert

bert wrote:

some time ago you were required to have an indication that your trailer
indicators were working. Originally that was visible and still is on my
Defender but then switched to audible, to save the manufacturers putting
in a cable and dash light which in most cars was never used. Don't know
what it is now

My car has a a single extra "trailer indicator" lamp on the dash, and if
there is a fault, it displays a message to the effect that trailer
lights aren't working ... not sure if the circuitry for that already
exists, or was fitted as part of the towbar kit.

In article , Andy Burns
writes
bert wrote:

some time ago you were required to have an indication that your
trailer indicators were working. Originally that was visible and
still is on my Defender but then switched to audible, to save the
manufacturers putting in a cable and dash light which in most cars
was never used. Don't know what it is now

My car has a a single extra "trailer indicator" lamp on the dash, and
if there is a fault, it displays a message to the effect that trailer
lights aren't working ... not sure if the circuitry for that already
exists, or was fitted as part of the towbar kit.
Defender (Old type) don't do messages.
--
bert