BMW 13-pin Towbar Wiring

[X5Sport]

It seems that BMW have not been fully installing the wiring for 13-pin electrics on their factory fitted towbars.  I don't remember seeing anything in the Sales brochures that indicate not all the wiring is in place and so I'm going to ask my local dealer to sort it out - especially having paid a not insignificant fee for a factory system.

Having checked our Mini Countryman, it too has three pins missing (10, 11 & 12 - though 12 is probably blank due to it not being used for anything - 10 should be a switched +ve with 11 as it's related GND.  The constant live (Pins 9+ and 13-) are there.  The same exists on our Mini with an OEM Tow bar.

Have those of you with OEM towbars been able to persuade your dealers to do the job at no charge, or are the Dealers using some cop-out for not doing it?  There is a proper kit available from Westfalia so it's not as if it can't be put right!

I'm curious as to why BMW chose not to put all the wiring in, or at least make it very clear to buyers that the wiring is limited and incomplete.  They could even add the additional cabling as an upgrade - though given the cost of the option it damn well ought to be included!

Richard

[Jayx5]

My mate had the same problem with his x1 and bmw sorted it for free.

[X5Sport]

I've had a reply from the Sales Team saying it's going to be referred to the service team on Monday.  I'll see what happens.

I don't know if the VPC at Thorne, the Dealer or the Factory actually fit the kits initially.  The 'standard' Westfalia kit has two optional 'add-on' systems.  One for a constant 12v and the other for a switched 12v supply.  The constant supply is there, just not the switched one.

I have seen comments that the wiring in use by UK vehicles is non-typical within the rest of the EU and it may be because of this that BMW choose not to do anything at the point of sale hoping no one will notice.  Given there is a country specific pack for all BMW/Mini models, one would have thought the full wiring would be included.

I'll let people know as things progress, but for those ordering new BMWs or Mini's with factory tow systems you should be aware there is an issue with the OEM wiring and one circuit is 'missing' but not discussed anywhere in the sakes brochures.

Richard

[Steamyrotter]

If its any help Richard, the after market kits for the E53 rarely have all of the above connected either...
I had to rig the switched 12v myself.

[X5Sport]

Got mine back today with a full OEM wiring 'repair' kit now installed and that included a spanking new 'Y' cable for 13-pin to twin 7-pin wiring.  All free.

Only took 7 months to get the bits, and then they discovered they also need additional fuse box parts.. :doh:

Richard

[Tin]

Hi,

Quick query on the factory fit Towhook option, whats the "Increased Towing Capacity" option? is the towbar mounted differently if it wasn't fitted at the factory? Or is the shell/bumper bar strengthen to cope with the additional loads?

Am looking for a e70 at the moment, and hoping to get one with a towhook as standard, but they're not the best spec'd cars.

thanks

[X5Sport]

Increased towing capacity lifts it from around 2.5 tonnes to 3.5 tonnes.  It's the same towbar and mounting but the car has a more powerful engine fan and additional radiators for gearbox cooling.

You can fit the towbar yourself afterwards and you need to cut the rear bumper.  Factory fit is better because you get a fully integrated system, although the wiring will have the problems highlighted in this thread.

Richard

[chrisn7]

Ok, so its an older thread, but bear with me-I thought it better to add to this than start a new one. When I bought the X5 last Aug, a Witter towbar had been fitted in Dec 2013, so the wiring should have been ok, but I wasn't able to test it. First trip out with the caravan showed that something was amiss so attention needed. Behind the right rear lamp was a typical set of scotchlok connectors, so I decided to move towards OEM.

Now checking the WDS showed the piece of BMW harness from the car plug to the 13 pin socket did not contain the full set of 13 pins as stated above, so I acquired the trailer module from ebay, and that harness from the dealer. Now this has a connector to plug in to the13 pin socket, with 3 vacant holes, so I just cut this off and wired straight into the 13 pin.

For caravan use a switched supply and associated earth are required to run the caravan fridge, so I recovered the respective standard grey and white/black cables from the 13 core cable originally fitted. The BMW harness from the rear valance to the 13 pin socket is not wrapped but run in a tubular sheath, and luckily there is just enough room left in this to run those 2 cables, thus maintaining the original water-proofing integrity.

To provide the switched power,I utilised the combi relay fitted with the towbar, positioned just below the boot floor lift handle, as this is convenient place from which to run a power cable to the boot fuse box, following the existing harness. I was surprised to discover that Fuse 87 had a 30 amp fuse present, but no terminal on the output side! So this was an ideal and neat place for power take off.

Now these combi relays only close to supply power once the engine has been started and a certain voltage is recognised by the unit. They usually have 2 outputs, one for the fridge, and the other used to be run to pin 12 to charge the caravan battery, so I decided to make use of this. As you know there are 2 accessory plugs on the R/H side of the boot, which are permanently live. I ran my second switched live to one of these plugs, by releasing the original spade terminal, and insulating this safely out of the way. The reason for this is that we have an additional 12v fridge for on site use, and this can now be plugged in without risking flattening the battery during stops, giving us an in car facility we have not had before. The set up is virtually OEM, is easily removable, has got rid of the wretched scotchloks, and freed up some space in the R/H boot cubby. Hope its of interest

[briankerrys47]

[quote="chrisn7"]
Ok, so its an older thread, but bear with me-I thought it better to add to this than start a new one. When I bought the X5 last Aug, a Witter towbar had been fitted in Dec 2013, so the wiring should have been ok, but I wasn't able to test it. First trip out with the caravan showed that something was amiss so attention needed. Behind the right rear lamp was a typical set of scotchlok connectors, so I decided to move towards OEM.

Now checking the WDS showed the piece of BMW harness from the car plug to the 13 pin socket did not contain the full set of 13 pins as stated above, so I acquired the trailer module from ebay, and that harness from the dealer. Now this has a connector to plug in to the13 pin socket, with 3 vacant holes, so I just cut this off and wired straight into the 13 pin.

For caravan use a switched supply and associated earth are required to run the caravan fridge, so I recovered the respective standard grey and white/black cables from the 13 core cable originally fitted. The BMW harness from the rear valance to the 13 pin socket is not wrapped but run in a tubular sheath, and luckily there is just enough room left in this to run those 2 cables, thus maintaining the original water-proofing integrity.

To provide the switched power,I utilised the combi relay fitted with the towbar, positioned just below the boot floor lift handle, as this is convenient place from which to run a power cable to the boot fuse box, following the existing harness. I was surprised to discover that Fuse 87 had a 30 amp fuse present, but no terminal on the output side! So this was an ideal and neat place for power take off.

Now these combi relays only close to supply power once the engine has been started and a certain voltage is recognised by the unit. They usually have 2 outputs, one for the fridge, and the other used to be run to pin 12 to charge the caravan battery, so I decided to make use of this. As you know there are 2 accessory plugs on the R/H side of the boot, which are permanently live. I ran my second switched live to one of these plugs, by releasing the original spade terminal, and insulating this safely out of the way. The reason for this is that we have an additional 12v fridge for on site use, and this can now be plugged in without risking flattening the battery during stops, giving us an in car facility we have not had before. The set up is virtually OEM, is easily removable, has got rid of the wretched scotchloks, and freed up some space in the R/H boot cubby. Hope its of interest
[/quote]Very Informative post Chris thank you for your time sure it will be appreciated by others.

[chrisn7]

Glad to be of help. Here's a bit more:

During this work,  I noticed that the cabin lights timed out but the tailgate lights do not, at least on my car they don't, which led to a low battery and no start. You have to press and hold the front centre roof button to turn everything off which is mildly inconvenient. To avoid this happening on site when caravanning and the tailgate is open for longer periods, I made a small mod.

The earths for the 2 tailgate interior lights are merged behind the trim near the r/h pull handle, and pass as a single wire to the earth comb directly behind the 2 accessory sockets. Fortunately this earth wire is the only one of its diameter amongst the multiple earth wires there. I mounted a small round rocker (Maplins £2.50) switch in plastic below the 2 sockets (20mm hole). Then cut that earth, splicing in maybe 15 cms of brown cable to each end (heatshrink), and thence to spade terminals to connect to the switch. Although I removed the trim panel containing the sockets to do the job on the bench, I would not recommend doing this, as it requires a fair amount of dismantling to get it out, and there is room to do it in situ.