Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

Is this a sort of standard aftermarket set-up for a tow bar conversion -
and anyone know where I could find a schematic?

The car is near the end of its life, but does still get used for towing
the trailer around - he has a newer car for the caravan.

I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.

--
*And the cardiologist' s diet: - If it tastes good spit it out.

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

On 01/10/2018 00:32, Dave Plowman (News) wrote:
Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

Is this a sort of standard aftermarket set-up for a tow bar conversion -
and anyone know where I could find a schematic?

The car is near the end of its life, but does still get used for towing
the trailer around - he has a newer car for the caravan.

I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.



If its the cheap after market towing kits then all they do is switch the
12V to the appropriate lamps using a "relay" so the car electrics don't
notice or blow a fuse.

The really old ones used mechanical relays, more recent may have some
electronics.

The only difficult bit is to detect when the indicators are working as
it has to make a sound when the indicator lights on the trailer are
flashing but not if only the cars indicators are flashing even if the
trailer is connected.

So there will be some sort of current sensing device in series with the
indicators. Maybe just a relay.

A new box is pretty cheap.

https://www.amazon.co.uk/Universal-B.../dp/B01MFDI2CM

On 01/10/2018 09:58, dennis@home wrote:
On 01/10/2018 00:32, Dave Plowman (News) wrote:


A new box is pretty cheap.

https://www.amazon.co.uk/Universal-B.../dp/B01MFDI2CM

+1,

you won't have wasted much time on the old one before you will have
justified that spend.

Dave Plowman (News) wrote :
The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

The mention of a buzzer suggests it is an after-market item, rather
than the BMW specific item. Two items suggests one for road lights, one
for the supplementary fridge, battery etc., usually a voltage triggered
relay, switching on when the alternator begins charging.

The proper BMW item tests all of the trailer lighting and immediately
reports faults on the dash, rather than just a buzzer for the
indicators.

Nothing working suggests to me that the main 12v feed is absent or fuse
has blown. The after-market unit uses relays and a separate 12v feed,
to avoid loading up the lighting circuits and causing can-bus faults.

Dave Plowman (News) wrote :
The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

The mention of a buzzer suggests it is an after-market item, rather
than the BMW specific item. Two items suggests one for road lights, one
for the supplementary fridge, battery etc., usually a voltage triggered
relay, switching on when the alternator begins charging.

The proper BMW item tests all of the trailer lighting and immediately
reports faults on the dash, rather than just a buzzer for the
indicators.

Nothing working suggests to me that the main 12v feed is absent or fuse
has blown. The after-market unit uses relays and a separate 12v feed,
to avoid loading up the lighting circuits and causing can-bus faults.

In article ,
dennis@home wrote:
I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.



If its the cheap after market towing kits then all they do is switch the
12V to the appropriate lamps using a "relay" so the car electrics don't
notice or blow a fuse.

What I sort of expected - not being a towing type, so never had to deal
with one.

The really old ones used mechanical relays, more recent may have some
electronics.

I'd expect the side light circuit to cope with the extra load since it is
a small extra percentage? The brakes lights would be double, so a relay
etc for that?

The only difficult bit is to detect when the indicators are working as
it has to make a sound when the indicator lights on the trailer are
flashing but not if only the cars indicators are flashing even if the
trailer is connected.

Ah - that's likely what my brother said on the phone.

So there will be some sort of current sensing device in series with the
indicators. Maybe just a relay.

A new box is pretty cheap.

https://www.amazon.co.uk/Universal-B.../dp/B01MFDI2CM

Thanks Dennis. Vehicle wiring isn't one of my brothers best skills, So
unless I can find identical replacements I'll likely try and work out what
the old ones did and repair, once they arrive here. My brother doesn't do
computers, and trying to get SIL to search for car bits can result in no
supper. ;-)

--
*If you think nobody cares about you, try missing a couple of payments *

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

In article ,
newshound wrote:
On 01/10/2018 09:58, dennis@home wrote:
On 01/10/2018 00:32, Dave Plowman (News) wrote:


A new box is pretty cheap.

https://www.amazon.co.uk/Universal-B.../dp/B01MFDI2CM

+1,

you won't have wasted much time on the old one before you will have
justified that spend.

Oh indeed. But unless I can find identical replacements (which will be
easier to do when I see them anyway) it might not be easy for him to fit a
different one. And in this case cost is an issue as the car is near the
end of its life. So not worth paying a pro to do it.

The Amazon one appears to handle the power side only, not the warning for
the indicators. Perhaps that's why the two boxes.

--
*Honk if you love peace and quiet*

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

Dave Plowman (News) wrote:

In article ,
dennis@home wrote:

I'd expect the side light circuit to cope with the extra load since it is
a small extra percentage? The brakes lights would be double, so a relay
etc for that?

There is the complication that the car may well have been
designed with sensing for its own bulb failure, so will not be
happy if the load differs from what it expects.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On Mon, 01 Oct 2018 00:32:50 +0100, Dave Plowman (News) wrote:

Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones
do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work
OK then.

This sounds like a cheap aftermarket wiring job by whoever fitted the
towbar. A proper job would have been to use a supplementary BMW loom
which would not have any boxes or whatever to connect to the main car
wiring.

It sounds as though either a fuse has blown in the power to the 'boxes'
or maybe a relay has gone within the boxes.

As the car is near end of life and he has another already wired up I
would suggest he does not waste time or money but simply use the other
car for both trailer and caravan.

The only issues he may then have are (1) getting an adaptor if trailer is
7 pin and car 13 pin and these are cheap enough and (2) remebering to
degrease the towball after trailer towing if the caravan has a built in
stabiliser.




--
Ermin

Dave Plowman (News) wrote on 01/10/2018 :
I'd expect the side light circuit to cope with the extra load since it is
a small extra percentage? The brakes lights would be double, so a relay
etc for that?

It is a matter of not upsetting the can-bus system. Most cars now use
can-bus, to avoid much of the mass of wiring that a modern car would
need. The can-bus switches the lights remotely using data and monitors
whether they are drawing the expected current remotely. Add extra loads
and the system can be upset. The extra load of a relay, would not be
noticed.

In article ,
Chris J Dixon wrote:
Dave Plowman (News) wrote:

In article ,
dennis@home wrote:

I'd expect the side light circuit to cope with the extra load since it is
a small extra percentage? The brakes lights would be double, so a relay
etc for that?

There is the complication that the car may well have been
designed with sensing for its own bulb failure, so will not be
happy if the load differs from what it expects.

Ah - of course.

--
*Beware - animal lover - brakes for pussy*

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

In article ,
Ermin wrote:
There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work
OK then.

This sounds like a cheap aftermarket wiring job by whoever fitted the
towbar. A proper job would have been to use a supplementary BMW loom
which would not have any boxes or whatever to connect to the main car
wiring.

Right. Although this model wasn't really designed for towing. Rear
suspension was meant to be upgraded too. Did say at the time he'd have
done better with a 5 Series Touring which has air suspension and made for
the job. But in both cases manuals were rather rare in his part of the
world.

Not a cheap job, but the usual cheap wiring. Scotchlock connectors
everywhere.

It sounds as though either a fuse has blown in the power to the 'boxes'
or maybe a relay has gone within the boxes.

The are a couple of external fuses which have been checked If it uses
standard relays, I might well have some 'in stock' - or substitutes easily
fitted.

As the car is near end of life and he has another already wired up I
would suggest he does not waste time or money but simply use the other
car for both trailer and caravan.

'Other car' is the wife's - and kept for clean things. The trailer is used
to take rubbish and junk etc to the tip. And so on. Of which he's been
doing a lot recently, and not just for themselves.

The only issues he may then have are (1) getting an adaptor if trailer
is 7 pin and car 13 pin and these are cheap enough and (2) remebering
to degrease the towball after trailer towing if the caravan has a built
in stabiliser.

Both cars are compatible.

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

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

In article ,
Harry Bloomfield wrote:
Dave Plowman (News) wrote on 01/10/2018 :
I'd expect the side light circuit to cope with the extra load since it is
a small extra percentage? The brakes lights would be double, so a relay
etc for that?

It is a matter of not upsetting the can-bus system. Most cars now use
can-bus, to avoid much of the mass of wiring that a modern car would
need. The can-bus switches the lights remotely using data and monitors
whether they are drawing the expected current remotely. Add extra loads
and the system can be upset. The extra load of a relay, would not be
noticed.

I'm not sure if this model uses canbus. Although my earlier 5 Series did.

--
*Some days you're the dog, some days the hydrant.

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

In article , "Dave Plowman (News)"
writes
Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

Is this a sort of standard aftermarket set-up for a tow bar conversion -
and anyone know where I could find a schematic?

The car is near the end of its life, but does still get used for towing
the trailer around - he has a newer car for the caravan.

I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.

Towing kits can be pretty sophisticated these days especially when wired
either to euro 11 pin or even 12n+s for a caravan.
Mine packed up just within warranty due to water ingress in the socket -
the cap hadn't been fitted quite correctly.
They will depend on a voltage sensitive relay driven by the alternator
output. Might be worth trying to locate and check that.
Mine is a rats nest of wires and boxes in what is laughingly called a
safe under the passenger seat.
--
bert

Also of course, is the actual trailer wiring OK and the connector good and
than cables that need to bend unbroken internally.

I'd expect items that flex or are exposed to the elements to be the first
places to look.
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.!
"dennis@home" wrote in message
...
On 01/10/2018 00:32, Dave Plowman (News) wrote:
Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones
do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

Is this a sort of standard aftermarket set-up for a tow bar conversion -
and anyone know where I could find a schematic?

The car is near the end of its life, but does still get used for towing
the trailer around - he has a newer car for the caravan.

I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.



If its the cheap after market towing kits then all they do is switch the
12V to the appropriate lamps using a "relay" so the car electrics don't
notice or blow a fuse.

The really old ones used mechanical relays, more recent may have some
electronics.

The only difficult bit is to detect when the indicators are working as it
has to make a sound when the indicator lights on the trailer are flashing
but not if only the cars indicators are flashing even if the trailer is
connected.

So there will be some sort of current sensing device in series with the
indicators. Maybe just a relay.

A new box is pretty cheap.

https://www.amazon.co.uk/Universal-B.../dp/B01MFDI2CM

Dave Plowman (News) explained :
Not a cheap job, but the usual cheap wiring. Scotchlock connectors
everywhere.

Scotchlock connection never last long, can never be relied upon. The
slightest hint of moisture and the connection degrades and likely the
wire tapped onto will break. Soldered and sealed is much better.

In article ,
Harry Bloomfield wrote:
Dave Plowman (News) explained :
Not a cheap job, but the usual cheap wiring. Scotchlock connectors
everywhere.

Scotchlock connection never last long, can never be relied upon. The
slightest hint of moisture and the connection degrades and likely the
wire tapped onto will break. Soldered and sealed is much better.

Yup - spawn of the devil. ;-)

--
*ONE NICE THING ABOUT EGOTISTS: THEY DON'T TALK ABOUT OTHER PEOPLE.

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

In article , Harry Bloomfield
writes
Dave Plowman (News) explained :
Not a cheap job, but the usual cheap wiring. Scotchlock connectors
everywhere.

Scotchlock connection never last long, can never be relied upon. The
slightest hint of moisture and the connection degrades and likely the
wire tapped onto will break. Soldered and sealed is much better.
Just the existence of scotchlocks suggest a botched job, Cars have had
plug in connectors for trailer wiring for years.
--
bert

bert pretended :
Just the existence of scotchlocks suggest a botched job, Cars have had plug
in connectors for trailer wiring for years.

--

Some have, some haven't. My car didn't.

It had its ECU's already set up to recognise lighting faults on a
trailer, a main 12v feed ready to use and to add an extra few inches to
its reverse sensor, for a tow ball, even partially bracketed for the
bar, but an extra ECU had to be bought, which needed to be tapped into
the existing wiring.

On Monday, October 1, 2018 at 2:42:15 PM UTC+1, bert wrote:
In article , "Dave Plowman (News)"
writes
Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

Is this a sort of standard aftermarket set-up for a tow bar conversion -
and anyone know where I could find a schematic?

The car is near the end of its life, but does still get used for towing
the trailer around - he has a newer car for the caravan.

I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.

Towing kits can be pretty sophisticated these days especially when wired
either to euro 11 pin or even 12n+s for a caravan.
Mine packed up just within warranty due to water ingress in the socket -
the cap hadn't been fitted quite correctly.
They will depend on a voltage sensitive relay driven by the alternator
output. Might be worth trying to locate and check that.
Mine is a rats nest of wires and boxes in what is laughingly called a
safe under the passenger seat.
--
bert

ISTR buying a BMW 525 about 15 yreArs ago and it required special BMW bits to enable electrical connections to the tow bar. Local tow bar supplier wouldn't wire up the tow bar for me so I ran without for a couple of years.

BMW electrics cba be quite finnicky. A friend got a 'handyman' to fit a radio to a new 3 series some time back. She never got the electrics functioning correctly again despite the efforts of a very good BMW garage.

On 01/10/2018 00:32, Dave Plowman (News) wrote:
Brother - who lives at the other end of the country - has a BMW E46 330t
which was pro fitted with a tow bar when he bought it some 8 years ago.
Cost an arm and leg.

The car lights still work as they should, but none of the trailer ones do.
It also no longer sounds the buzzer or whatever when you connect it.

There are two boxes that appear to be part of the extra wiring to the
trailer sockets - one with fuses. One of them seemed to buzz at one time
(relay?) even without the trailer lights connected - but they did work OK
then.

Is this a sort of standard aftermarket set-up for a tow bar conversion -
and anyone know where I could find a schematic?

The car is near the end of its life, but does still get used for towing
the trailer around - he has a newer car for the caravan.

I've offered to look at the boxes (since he says he's checked all the
wiring etc) but it would help if I knew exactly what they did.


I would inspect the wiring going to the boxes. If there are any thin
wires, smaller than needed to supply current to an incandescent light
bulb, then the boxes may connect to the Can-bus which will be more awkward.
This is a source of suitable parts and info https://www.pfjones.co.uk/


--
Michael Chare

In article ,
fred wrote:
ISTR buying a BMW 525 about 15 yreArs ago and it required special BMW
bits to enable electrical connections to the tow bar. Local tow bar
supplier wouldn't wire up the tow bar for me so I ran without for a
couple of years.

5 Series have used canbus for about 20 years. That is always going to be
more tricky to add to than ordinary wiring. I'm not sure when the cheaper
3 Series got it.

BMW electrics cba be quite finnicky. A friend got a 'handyman' to fit a
radio to a new 3 series some time back. She never got the electrics
functioning correctly again despite the efforts of a very good BMW
garage.

My 97 5 Series had diversity aerials and an external power amp. And it
didn't have the top of the range audio system. I'm not surprised Joe
Bloggs could have problems fitting a different head unit. But it can be
done.

--
*When the going gets tough, use duct tape

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

Thanks chaps. I'll be talking to brother this evening and will jaw it over.

--
*Why is it that doctors call what they do "practice"?

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

Dave Plowman (News) explained :
My 97 5 Series had diversity aerials and an external power amp. And it
didn't have the top of the range audio system. I'm not surprised Joe
Bloggs could have problems fitting a different head unit. But it can be
done.

Mine has the diversity antennas for both the radio and TV antennas.
Quite a complex and clever system, where the receiver decides which set
of antennas provides the better reception at any instant.

In article ,
Harry Bloomfield wrote:
Dave Plowman (News) explained :
My 97 5 Series had diversity aerials and an external power amp. And it
didn't have the top of the range audio system. I'm not surprised Joe
Bloggs could have problems fitting a different head unit. But it can be
done.

Mine has the diversity antennas for both the radio and TV antennas.
Quite a complex and clever system, where the receiver decides which set
of antennas provides the better reception at any instant.

Yes - first saw it on pro radio mics some 40 years ago.

--
*Save the whale - I'll have it for my supper*

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

In article ,
Cursitor Doom wrote:
On Mon, 01 Oct 2018 11:26:23 +0100, Nightjar wrote:

But I'm sure Boris will just stamp his foot and say it will be easy.

It *is* easy. The problem is you have the EU making things as difficult
as humanly possible for us to leave on good terms for perfectly sound
reasons - and that should have been blindingly obvious to everyone since
well before the Referendum even. Anyone who says, "I had no idea it
would all be this complicated" must be some kind of simpleton.

You've just described the public face of leavers before the referendum. It
was all going to be so easy - leave the EU, and they'd roll over and give
in to our every demand for a new deal. Other countries around the world
queueing up for our goods and services.

Since you were ever so wrong about that, why expect other of your guesses
to be believed?

--
*Caution: I drive like you do.

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

On Wed, 03 Oct 2018 01:00:18 +0100, Dave Plowman (News) wrote:

Quite a complex and clever system, where the receiver decides
which set
of antennas provides the better reception at any instant.

Yes - first saw it on pro radio mics some 40 years ago.

Easy to do with FM, just monitor the HF noise and choose the receiver
with the lowest noise.

Now the stuff that AC WiFi APs do is clever. With multiple antennas
and presumably signal phase between them enabling the direction of
maximum pick up/transmission to be steered to point at the clients,

--
Cheers
Dave.

In article l.net,
Dave Liquorice wrote:
On Wed, 03 Oct 2018 01:00:18 +0100, Dave Plowman (News) wrote:

Quite a complex and clever system, where the receiver decides
which set
of antennas provides the better reception at any instant.

Yes - first saw it on pro radio mics some 40 years ago.

Easy to do with FM, just monitor the HF noise and choose the receiver
with the lowest noise.

Yes. IIRC, radio mics used two receivers. My car said it selected the best
aerial. Although having screen aerials, still rubbish.

Now the stuff that AC WiFi APs do is clever. With multiple antennas
and presumably signal phase between them enabling the direction of
maximum pick up/transmission to be steered to point at the clients,

Likely simpler in some ways with digital. Latency gives you some time to
decide. ;-)

--
*The beatings will continue until morale improves *

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

Dave Plowman wrote:

Harry Bloomfield wrote:

It is a matter of not upsetting the can-bus system.

I'm not sure if this model uses canbus. Although my earlier 5 Series did.

If it does use canbus, it may do other things such as disable parking
sensors (and reversing lights on the car itself?) while reverse gear is
selected.

On 03/10/2018 16:55, Andy Burns wrote:
Dave Plowman wrote:

Harry Bloomfield wrote:

It is a matter of not upsetting the can-bus system.

I'm not sure if this model uses canbus.Â* Although my earlier 5 Series
did.

If it does use canbus, it may do other things such as disable parking
sensors (and reversing lights on the car itself?) while reverse gear is
selected.

Often disable rear foglights and change the mode of electronic stability
controls too.

SteveW