Towbar Wiring

[prunty]

When wiring mine I initially connected the trailer lights into the near side rear light cluster, expecting the feed to the lights to power the trailer lights and proceeded to blow the Bsi unit. I then fitted a smart relay behind the near side rear light cluster and took the signals from the rear light loom just before the wire entered the bulb holder (where I had originally connected the trailer lights). I then fed a permanent live feed from the battery to the relay with an in-line fuse (as is described above) close to the battery and it all worked fine.

Basically the permanent live is what feeds the trailer lights through the smart relay. The van lights connections are only used as signals to power the relay. In fact you can hear the relay clicking away as you switch on and of lights, indicators, etc, etc... This set up protects the van wiring if a fault develops in the trailer lights as there is no direct connection from the trailer wiring to the van wiring. With my original set up there was some minor fault, or indeed the extra load with the trailer lights overloaded the very delicate Bsi unit.

[Tenere]

When wiring mine I initially connected the trailer lights into the near side rear light cluster, expecting the feed to the lights to power the trailer lights and proceeded to blow the Bsi unit. I then fitted a smart relay behind the near side rear light cluster and took the signals from the rear light loom just before the wire entered the bulb holder (where I had originally connected the trailer lights). I then fed a permanent live feed from the battery to the relay with an in-line fuse (as is described above) close to the battery and it all worked fine.

Basically the permanent live is what feeds the trailer lights through the smart relay. The van lights connections are only used as signals to power the relay. In fact you can hear the relay clicking away as you switch on and of lights, indicators, etc, etc... This set up protects the van wiring if a fault develops in the trailer lights as there is no direct connection from the trailer wiring to the van wiring. With my original set up there was some minor fault, or indeed the extra load with the trailer lights overloaded the very delicate Bsi unit.

Blew the BSI unit? Crumbs! .....not just a fuse in the BSI unit?
I've just fitted a towbar and have come to the wiring part. It's a standard 12n that I was just going to gash into the rear cluster harnesses with horrible scotchlocks, but when I peeled the wrapping back the wires are very fine so I backed off to read up in case I overloaded. As far as I can tell there is no bulb failure warning system and it obviously has no CAN ports so I had decided just to drop the Scotchlocks for solder and carry on, perhaps with some LED trailer bulbs to lessen the draw, but if BSI's are at danger rather than fuses then I'm now worried. Should I be fitting a bypass relay as well or was this just a fluke?

Does anyone else have any stories relating to towbar wiring on the MK2 van?

[evdama]

When wiring mine I initially connected the trailer lights into the near side rear light cluster, expecting the feed to the lights to power the trailer lights and proceeded to blow the Bsi unit. I then fitted a smart relay behind the near side rear light cluster and took the signals from the rear light loom just before the wire entered the bulb holder (where I had originally connected the trailer lights). I then fed a permanent live feed from the battery to the relay with an in-line fuse (as is described above) close to the battery and it all worked fine.

Basically the permanent live is what feeds the trailer lights through the smart relay. The van lights connections are only used as signals to power the relay. In fact you can hear the relay clicking away as you switch on and of lights, indicators, etc, etc... This set up protects the van wiring if a fault develops in the trailer lights as there is no direct connection from the trailer wiring to the van wiring. With my original set up there was some minor fault, or indeed the extra load with the trailer lights overloaded the very delicate Bsi unit.

Blew the BSI unit? Crumbs! .....not just a fuse in the BSI unit?
I've just fitted a towbar and have come to the wiring part. It's a standard 12n that I was just going to gash into the rear cluster harnesses with horrible scotchlocks, but when I peeled the wrapping back the wires are very fine so I backed off to read up in case I overloaded. As far as I can tell there is no bulb failure warning system and it obviously has no CAN ports so I had decided just to drop the Scotchlocks for solder and carry on, perhaps with some LED trailer bulbs to lessen the draw, but if BSI's are at danger rather than fuses then I'm now worried. Should I be fitting a bypass relay as well or was this just a fluke?

Does anyone else have any stories relating to towbar wiring on the MK2 van?

Ive done one on a late MK2-I wired direct to the vans loom and it worked just fine although I did my subsequent vehicles with a relay and wouldnt go back now.
Its a tiny bit of extra work but a big load of benefit.

The fine ribbon style wiring can be carefully peeled apart to release each core.
Theres absolutely nothing wrong with scotchloks - if youre having problems then youre doing something wrong. - use the red ones for small cores.
Ive had nothing but solid connection with them even to the point of being able to reuse them on the next vehicle.
Tightwad.
Ive got some third generation ones providing excellent service right now.

The ground should be made with a bigger core and attached to the stud by the nearside light cluster.The cable can be dropped down through the nearside rear door pillar and across to the socket
The offside lamps can be tapped into and fed up and over inside the rear door frame to meet the rest of the wires.

[j90xxx]

Must admit I cheated. :whistle:
1. Fitted the tow bar myself. Doddle.
2. Then ran the 7-core cable into the rear.
3. Drove to local tow bar specialist.
4. THEY wired it up.
5. I gave them £35.
:woop:

[evdama]

Must admit I cheated. :whistle:
1. Fitted the tow bar myself. Doddle.
2. Then ran the 7-core cable into the rear.
3. Drove to local tow bar specialist.
4. THEY wired it up.
5. I gave them £35.
:woop:

EEEsh! - the wiring is even easier than the fitting!

[Tenere]

[/quote]
Ive done one on a late MK2-I wired direct to the vans loom and it worked just fine although I did my subsequent vehicles with a relay and wouldnt go back now.
Its a tiny bit of extra work but a big load of benefit.

The fine ribbon style wiring can be carefully peeled apart to release each core.
Theres absolutely nothing wrong with scotchloks - if youre having problems then youre doing something wrong. - use the red ones for small cores.
Ive had nothing but solid connection with them even to the point of being able to reuse them on the next vehicle.
Tightwad.
Ive got some third generation ones providing excellent service right now.

The ground should be made with a bigger core and attached to the stud by the nearside light cluster.The cable can be dropped down through the nearside rear door pillar and across to the socket
The offside lamps can be tapped into and fed up and over inside the rear door frame to meet the rest of the wires.
[/quote]

:thumbsup:Cheers Evdama, I've been looking at relays on Ebay and at around £10-£16 it seems worthwhile. It seems like the recommendation is to fuse them at 15A but can I ask if you know of a good spot to tap the feed rather than all the way back to the battery?
- I may even use a Scotchlock! although I still don't like them much as I have had them damage core strands and then there's the unsightly 'bunch of grapes' to look at!

Thanks for your kind advice

[evdama]

Ive done one on a late MK2-I wired direct to the vans loom and it worked just fine although I did my subsequent vehicles with a relay and wouldnt go back now.
Its a tiny bit of extra work but a big load of benefit.

The fine ribbon style wiring can be carefully peeled apart to release each core.
Theres absolutely nothing wrong with scotchloks - if youre having problems then youre doing something wrong. - use the red ones for small cores.
Ive had nothing but solid connection with them even to the point of being able to reuse them on the next vehicle.
Tightwad.
Ive got some third generation ones providing excellent service right now.

The ground should be made with a bigger core and attached to the stud by the nearside light cluster.The cable can be dropped down through the nearside rear door pillar and across to the socket
The offside lamps can be tapped into and fed up and over inside the rear door frame to meet the rest of the wires.
[/quote]

:thumbsup:Cheers Evdama, I've been looking at relays on Ebay and at around £10-£16 it seems worthwhile. It seems like the recommendation is to fuse them at 25A but can I ask if you know of a good spot to tap the feed rather than all the way back to the battery?
- I may even use a Scotchlock! although I still don't like them much as I have had them damage core strands and then there's the unsightly 'bunch of grapes' to look at!

Thanks for your kind advice
[/quote]
Not forgetting a relay will provide you with an integrated indicator bleeper as well!
The one I have has two 7.5a feeds.
Behind the glovebox is usually a place to find some tapping points.Obviously choose a nice big conductor and fuse your feed right there.
But on a MK2 its much much easier to get through the bulkhead (there should be a big grommet with spare capacity) than on MK3's so you might as well go all the way to the battery.
Consider running a couple more live feeds while youre at it in case you ever want to go twin or 13pin socket.
13pin will allow you more features all on one single (and better designed)socket/plug system.
The feeds can be neatly tucked under carpets and rubber doorseal lips all the way back to the relay which can be concealed in a void near the rear lamp cluster.

[j90xxx]

Must admit I cheated. :whistle:
1. Fitted the tow bar myself. Doddle.
2. Then ran the 7-core cable into the rear.
3. Drove to local tow bar specialist.
4. THEY wired it up.
5. I gave them £35.
:woop:

EEEsh! - the wiring is even easier than the fitting!

Always done my own before.
But this is French, with French wiring, and a fragile BSI.
Didn't trust myself, and was going away that weekend.
Left it to the 'experts'. :thumbsup:
(There's no smiliey of a chicken!)

[Romahomepete]

MK3 There is a thick white wire behind the the nearside trim panel in the boot area. It is live all the time.

Peter

[harryw]

Hi,

I've been taking a look at the various threads on towbar wiring and feel I now know more but not quite enough to proceed to wire mine with confidence. I have a 2007 (Dec) Mark 1 Model and have fitted the tow bar and am studying the wiring harness that came with it. First the car is a German model and the kit I have includes a 13 pin socket. I also have a Flash Control box made by a "AC" called a UN-05. The instructions for fitting the harness (Part UE 0004) call for the left and right rear indicator and the rear fog lamp feed to be cut with both ends then being fed back into the harness. In the case of the stop lights, side lights and reversing lights it looks like the plan is to simply scotch lock on to the appropriate feeds.

I've checked the harness and it looks like the (+)ve is fed to the UA-05 so I guess this might be a relay box. Warning notices on the wiring in the lamp clusters state that nothing should be connected to any wires that will draw more than 10mA which is clearly not going to be OK if the stop lamps, reversing lights and side lights are not relay fed. I guessing that where wires are being cut only some kind of sensing coil is involved. I can't find any detailed information about the UA-05 anywhere on the net except for adverts on German ebay.

All input very welcome.

Harry