Urgent Help, Tow Bar Electrics. (1 Viewer)

[haganap]

Ok, where to start, here's a story, please read on. If it's not sorted soon, look for me at the nearest bridge, my head is offically cod and battered.

I purchased a tow bar and electrics from a friend of mine dedicated to fit my van. It was working when it came off so I had no reason to doubt its working now.

I installed it on the van which consists of doing the following, Unplugging 1 cable, leaving 2 scotch type connections, these are then pluged in to the new loom made for the swift van. Then locating a plug near to where the towball is fitted un plugging it and plugging the new one in. Then there is two plugs in to the westfalia box and a relay.
this = job done. other than connecting the earth strap.

So I done all this and plugged my tail board in, and no lights of any sort. All the lights on the motorhome work as they should do.

It was then suggested that maybe there was a fuse gone in the van? I therefore checked every fuse loacted this side or manchester and checked it, still no working. Then, I spoke to the seller of the towbar whom insisted it was working but happened to have a complete loom and westfalia box as a spare so I could check a few things out. all that plugged in and same problem.

So moving on, I had a good think about it and plugged the old loom back in so i could return the new one. I then disconnected the earth on the chasis that comes with the towing electrics and checked at the socket with my multi meter. I placed a prong in the earth of the plug socket, and probed the other pins, all of them showed live when I turned the van electrics on with hazzard lights. I then completed the same process at the tailboard lights and again showed power at the bulbs. However, when I then touched the earth cable to the chassis, the power seemed to dissapear ? giving no reading at teh towing socket, release the earth and power comes again?

I plugged the car in to be sure it was no the tail board and when plugged in, one indicator flashes on the car but nothing else, and then it's debateable as to what happens in the car electrics next.


My thoughts are that there must be an earth fault? is it because I have been unable to secure an appropriate earth with the earth strap? Even though I can rub it hard on the chasis to no evail, and why does the power die when I touch the earth on to the chasis?


Any ideas would be helpful, even simple ones, to ensure that I have considered simpe things

 

[bungy]

Hi Paul

Have you tried any Resistance checks - just to check for any shorts between any of the pins?

with the power disconnected obviously!!

 

[old-mo]

Paul..... I would seriously look to see if your friend has wired the plug/loom up correctly..

Sounds like a swop over on the earth and power to one Light..

These are helpful site`s.. .

http://www.pfjones.co.uk/tow-bar-electrics.html

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[haganap]

Paul..... I would seriously look to see if your friend has wired the plug/loom up correctly..

Sounds like a swop over on the earth and power to one Light..

These are helpful site`s.. .

http://www.pfjones.co.uk/tow-bar-electrics.html

Hi mo, thanks, they are factory looms. There is no wiring involved at all. I have two looms, the new one and the one that came off, same on both:Sad:

 

[acting_strange]

OK....take ALL of the board bulbs out and run the checks again..then replace the bulbs one at a time until the fault comes back...

I did once find that some idiot had put the wrong type of bulb in a fitting and this shorted the system to earth...

 

[andyman]

Sounds like a missing power supply. On both my Saab and Bmw I used a dedicated loom but still need a supply from the battery.

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[TheBig1]

dont forget your connecting to a can bus system. I agree that there is a live feed from the battery missing. as for the light board, that sounds like a bad earth if only one bulb works on a known good vehicle

 

[haganap]

Sounds like a missing power supply. On both my Saab and Bmw I used a dedicated loom but still need a supply from the battery.

as I said Andy, there is power at the plug, there is even power at the trailer board. until I hook up the Earth Lead.

These systems are simple and sirt of fookl proof, you unplug three plugs, plug in 3 plugs and jobs done. :Angry:

 

[TheBig1]

the last can bus towbar wiring kit I used had a 12v+ve to the battery as well. the system will show power without from the vehicle harness but not enough current to power the lights on the trailer. connecting the earth will complete the circuit and the body control module cuts power to the circuit thinking its a fault

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[bungy]

electrickery always takes the path of least resistance...are there any points in the system where you can do the good old half split method, by checking on the loom itself with it disconnected by doing a beep test with the meter
connect one probe on a pin on one and and then the other probe on each of the pins on the other end, you should only get one beep per pin (dont know the loom so making and assumption here), if you get more than one beep then there's something up with the loom, if not then it is either the vehicle end, or the board end

But saying all that thebig1 explanation makes more sense....i think ours has a direct connection as well

 

[Oscarbobs]

The big 1 is correct, i fitted one to my van last week and it required its own dedicated 12v supply.

Dave

 

[edgy]

Phew light at the end of the tunnel or is it power to the wire

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[Hayleylulu]

I think there's something wrong some where hope this helps you Paul

 

[bungy]

can you not test it with your shiny new S3...once youve worked it out that is

 

[haganap]

Ok Dave and the big 1 thanks for your advice. However, as I said, this is a system that's been fitted on other systems as per my own. It's an aftermarket fit, it's fitting instructions do not give any need for any other further wiring. Everything needed to fit it is there. As said its unplug and replug, all the other wiring is there already completed. But, big 1 what you described is a possibility but not due to the way you describe it. Is it possible that it is fused ? I was told it was fused at the cab battery with an in line 30 amp fuse. However I can not find it, there are a few fuses but none that are blown.. If there was a blown fuse it would be in line with what you are saying. The wire back to the battery is already carried out within the wiring loom that comes with the fitting. I sort of know this as the friend who sold it me fits them for swift as an aftermarket fit. However he only fits them because there is no wiring involved other than unplug and replug

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[robinmclaren]

hi paul , throw away your meter and use a 12v lamp tester , this will give a lit lamp when one end to chassis and one end to suspected live terminal , meters can give weird readings on car wiring with missing neutrals . good luck . has your bessacarr got the led rear tail lights , if so there is a resitor in line to stop the light fault indicator on dash illuminating , just had a problem with this on ours

 

[Incamania]

Towbar Electrics

Hi Paul
Accepting the fact that the unit has worked on a similar fitting and that you believe it to be serviceable, have you considered that the 12v wiring of the vans may differ due to additional 12v equipment being installed in yours?
My reasoning is that one of these units could be shunting the Tow Bar Circuitry, perhaps just isolating them might put you back to square 1, see if the problem disappears then reconnect them 1 at a time. Should be a simple check if all the extras have been fused.
ATB
Brian

 

[Jaws]

Ummm.. Something no one has mentioned is that your base van is Can Bus Paul. ( Basic info here mate )

It may require you to have the tan code changed in the control unit on the van..
Speak toi Fiat ( or Pug, depending on which unit you have )

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[haganap]

I have read that previously, John, again, I am informed that there is no need as it's already geared up to take the tow bar.

I have decided to have one more look at it on Tuesday when Im off and hunt for any fuse or break in the return to Ve that the big one mentions, as the way it is performing makes sense to what he says.

Failing that, I am going to contact an auto electrician and see if they can fix it. I am extremely disappointed to say the least. I brought it to put the bikes on to go on Holiday in 2 weeks, I expected it to plug and play, obviously it isn't as simple as that because some thing on the van refuses to allow it to be.

Should of just gone and got one fitted :Sad::Sad:

 

[Jaws]

Shame you are so far away mate.. Would have been happy to cast my eye over it for you.. Bored out of my brains at the moment !!

So much so that I may even contemplate starting my winter project bike early this year !

 

[darklord]

1) When I fitted a manufacturers tow kit to a Landrover, there were relays and fuses at the front near the vehicle fuse bank, including, as has been said,..dedicated lives which are fused. If the donor vehicle had this, but yours does not, or only has part of it...could be a problem.

2) if the set up came with any scotchlocks, get rid of them.......or sure as eggs is eggs, you will regret it.

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[TheBig1]

just reading back over this thread makes me realise that my description is somewhat lacking so will try again

in previous vehicles that dont use a can bus, which transmits info over the wiring loom, like the ducato van up to 2006, you could simply plug into the loom and take power direct from the lighting circuits.
since then though technology has moved on, giving us bulb failure warnings and more advanced body control modules. these modules constantly check for errors or higher current draw in a circuit than normal. If it senses that something is different, then it will kill power to the circuit and raise a fault code with the ecu

to get over this, there are 2 routes....
1 fit the genuine fiat part that then needs to be enabled in the ecu by plugging in a computer. these loom aditions will normally require a wire being fitted and plugged into the fusebox. these tend to be silly expensive so not many people fit these

2 fit an aftermarket kit such as the westfalia one. these kits use a dedicated bypass relay, which takes its signal from the vehicle lighting loom, but to protect the body control module circuits, takes power from a fused battery feed. so if you switch on an indicator say, the relay circuit for the relevant indicator is energised and closes the contact powering up the socket and any number of bulbs on the trailer as appropriate

If a motorhome is prewired for taking a plug in suplementary loom, you will find that as well as the connector on the chassis, there is also one inside the van. When I was looking for a kit to fit on my previous van, I recall reading the fitting instructions for either a swft or bessecar, not sure which, that noted a wire near the fusebox (in wardrobe?) required connecting to complete the install. As far as I can remember the intruction pdfs were on towequipe website, but just checked and cant see them now. It would be worth a phone call to them on monday as they supply the kits and have a fitting helpline 0800 043 0042

hope this makes more sense and is a little more helpfull?

 

[Gooney]

just reading back over this thread makes me realise that my description is somewhat lacking so will try again

in previous vehicles that dont use a can bus, which transmits info over the wiring loom, like the ducato van up to 2006, you could simply plug into the loom and take power direct from the lighting circuits.
since then though technology has moved on, giving us bulb failure warnings and more advanced body control modules. these modules constantly check for errors or higher current draw in a circuit than normal. If it senses that something is different, then it will kill power to the circuit and raise a fault code with the ecu

to get over this, there are 2 routes....
1 fit the genuine fiat part that then needs to be enabled in the ecu by plugging in a computer. these loom aditions will normally require a wire being fitted and plugged into the fusebox. these tend to be silly expensive so not many people fit these

2 fit an aftermarket kit such as the westfalia one. these kits use a dedicated bypass relay, which takes its signal from the vehicle lighting loom, but to protect the body control module circuits, takes power from a fused battery feed. so if you switch on an indicator say, the relay circuit for the relevant indicator is energised and closes the contact powering up the socket and any number of bulbs on the trailer as appropriate

If a motorhome is prewired for taking a plug in suplementary loom, you will find that as well as the connector on the chassis, there is also one inside the van. When I was looking for a kit to fit on my previous van, I recall reading the fitting instructions for either a swft or bessecar, not sure which, that noted a wire near the fusebox (in wardrobe?) required connecting to complete the install. As far as I can remember the intruction pdfs were on towequipe website, but just checked and cant see them now. It would be worth a phone call to them on monday as they supply the kits and have a fitting helpline 0800 043 0042

hope this makes more sense and is a little more helpfull?

Excellent description, thanks for that:thumb:

 

[haganap]

just reading back over this thread makes me realise that my description is somewhat lacking so will try again

in previous vehicles that dont use a can bus, which transmits info over the wiring loom, like the ducato van up to 2006, you could simply plug into the loom and take power direct from the lighting circuits.
since then though technology has moved on, giving us bulb failure warnings and more advanced body control modules. these modules constantly check for errors or higher current draw in a circuit than normal. If it senses that something is different, then it will kill power to the circuit and raise a fault code with the ecu

to get over this, there are 2 routes....
1 fit the genuine fiat part that then needs to be enabled in the ecu by plugging in a computer. these loom aditions will normally require a wire being fitted and plugged into the fusebox. these tend to be silly expensive so not many people fit these

2 fit an aftermarket kit such as the westfalia one. these kits use a dedicated bypass relay, which takes its signal from the vehicle lighting loom, but to protect the body control module circuits, takes power from a fused battery feed. so if you switch on an indicator say, the relay circuit for the relevant indicator is energised and closes the contact powering up the socket and any number of bulbs on the trailer as appropriate

If a motorhome is prewired for taking a plug in suplementary loom, you will find that as well as the connector on the chassis, there is also one inside the van. When I was looking for a kit to fit on my previous van, I recall reading the fitting instructions for either a swft or bessecar, not sure which, that noted a wire near the fusebox (in wardrobe?) required connecting to complete the install. As far as I can remember the intruction pdfs were on towequipe website, but just checked and cant see them now. It would be worth a phone call to them on monday as they supply the kits and have a fitting helpline 0800 043 0042

hope this makes more sense and is a little more helpfull?

Thank you very much for taking the time to reply in such detail, that's most helpful and descriptive and shows you have grasped the additional loom/westfalia unit I have been supplied.
I will give them a call. Im convinced it's something simple or hidden that has not made the circuit, maybe they can throw some light on it.

if not then its the dreaded auto electrician, but presumably, he's only going to be looking for the same thing as i am. :Sad:

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[robinmclaren]

the can bus system is far to clever for me as i just found out when going over to see how my new mhome security system is going , it seems my canbus based alarm signals doors to unlock, lights to flash, habitation door to unlock for only a few seconds unless opened, horn to follow alarm siren signal etc, etc, all progammed in and not wired to individual items, very clever , hopefully all completed by tuesday and ready to pick up , reversing camera now working on override switch to watch toad while driving , perimiter warn away system excellent and will be used on aires in france, i will ask neil when he calls for any clues on your towbar and forward any replies, give me the old days of wires and switches

good luck paul

 

[hilldweller]

the can bus system is far to clever for me as i just found out when going over to see how my new mhome security system is going , it seems my canbus based alarm signals doors to unlock, lights to flash, habitation door to unlock for only a few seconds unless opened, horn to follow alarm siren signal etc, etc, all progammed in and not wired to individual items, very clever
good luck paul

Remember CANBUS is just a cost cutting convenience for the makers.

But when it goes wrong, those with the analizers and codes can charge what they want for diagnostics.

We regularly get folk in here "My PC is doing this...." "My laptop won't do this..." and a lot of help can be given, but imagine a PC where you have no idea what operating system, no password to check the hard drive, no recovery disk. You may well try and hack into the National Lottery computer.

 

[haganap]

Ok, after all of what you said,. my van is in bits, I am in bits, there is no mention of any fuses, any do this do that. the instructions to fit are simple. I have therefore in order to gain any more help taken a picture of the instructions and ask again, anyone point out the probelm.

hope you can read it.

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[TheBig1]

socket C (inside van) should contain the 12v +ve. check its there with a meter. If it is make sure the connection is tight and 12v is live after the plug and socket are connected. from your desription, this looks like the problem. if its not there, the quick answer is to run another fused 12v and tie it in at the plug

the control unit is the bypass relay and the second relay appears to give a switched earth. check this is operating with the meter too

 

[haganap]

socket C (inside van) should contain the 12v +ve. check its there with a meter. If it is make sure the connection is tight and 12v is live after the plug and socket are connected. from your desription, this looks like the problem. if its not there, the quick answer is to run another fused 12v and tie it in at the plug

the control unit is the bypass relay and the second relay appears to give a switched earth. check this is operating with the meter too

Not that im going too, seems a little beyond me.
but the plug, inside the van (c) consists of just two wires, joined to gether. the plug going in from the tow bar loom, consists of 4.
When you say run a fused 12v do you mean to the hab battery? in to plug c? at that point it goes in too the towing loom

the control units and the bypass relay I have tried with new ones. Before any rewiring takes place I am going to put togethter the brand new loom with all the new bits again and try that just to make sure. It's on a 13 pin plug but I can use my tester to test it. I have made sure I have created a good earth,

its become a personal challenge now.

 

[TheBig1]

Not that im going too, seems a little beyond me.
but the plug, inside the van (c) consists of just two wires, joined to gether. the plug going in from the tow bar loom, consists of 4.
When you say run a fused 12v do you mean to the hab battery? in to plug c? at that point it goes in too the towing loom


the control units and the bypass relay I have tried with new ones. Before any rewiring takes place I am going to put togethter the brand new loom with all the new bits again and try that just to make sure. It's on a 13 pin plug but I can use my tester to test it. I have made sure I have created a good earth,

its become a personal challenge now.

thats where your problem is then, the van isnt prewired to accept the kit after all. I would GUESS that the largest wire in the plug in kit is the 12v +ve, and the missing pair is for an audible warning unit that buzzes with the indicators. make sure the plug is live with the engine running on the 2 linked pins mentioned

Getting a towbar fitter or auto electrician to fit a bypass relay and socket should only take about 1 1/2 hrs (16 connections) plus about £30 parts. it could take nearly as long to trace the wires on your van and fit the kit "properly". They may however take the route I mention and take a live feed to the plug from something close like the fridge or step thats only live with the ignition on. a quick and simple fix

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