BMW Towbar Electrics

Jan 18, 2017
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I have a 2014 BMW X5 with factory-fitted towbar. It does not have a fridge relay to run the fridge on 12V whilst towing. BMW and my local towbar specialist (Tow-Rite) say one cannot be fitted because the car's wiring loom is not designed to take it, others tell me it can be done at great expense by replacing part of the loom (so must be done by a BMW specialist), still others say it is possible to cut off the BMW supply to the 13-pin socket and start again (although I fear this might mess up the car's computer controls, including the camera which focuses on the tow-hitch when reversing with the towbar out). Do members have any advice?
 
Nov 11, 2009
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TopazMan said:
I have a 2014 BMW X5 with factory-fitted towbar. It does not have a fridge relay to run the fridge on 12V whilst towing. BMW and my local towbar specialist (Tow-Rite) say one cannot be fitted because the car's wiring loom is not designed to take it, others tell me it can be done at great expense by replacing part of the loom (so must be done by a BMW specialist), still others say it is possible to cut off the BMW supply to the 13-pin socket and start again (although I fear this might mess up the car's computer controls, including the camera which focuses on the tow-hitch when reversing with the towbar out). Do members have any advice?

I would talk to an approved towbar installer or contact the towbar manufacturers technical departments. Who makes the OEM towbar for your car. Unless you can be assured that any modifications aren’t going to cause problems with the cars systems I would live with it. Just use the fridge as a large insulated cool box. Bring its temperature down overnight before a trip using 240 v or gas. Move your cool food drinks from the house fridge and together with some freezer packs just before departure.
 
Jan 3, 2019
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you could do this yourself if you are competent with wiring, the question would be whether you have cables attached to pins 10 and 11 (the positive and negative terminals for the fridge) even if they arn't connected to anything in your car.
if you do and can locate these cables then pin 11 is your earth (connect to earth in your cars boot area) and pin 12 is live but ONLY when the engine is running, this is important because if you hook it up to the battery so it's live all the time then yes the fridge will work, however if your cars battery goes flat for whatever reason then it will try to crank the engine from the leisure battery as it is hooked up to the same live circuit...and you don't want 120 amps running through those cables..they will melt at the very least...and catch fire at worst.
this fridge live wire should also be fed via a relay (any basic 4 pin relay is ok) and obviously through an inline fuse (20 amps should be ok)
I recently wired a 13 pin tow socket into my bmw, but didn't use the cars own wiring harness for it, I bought my own relays and canbus unit which worked out a lot cheaper and easier to install.
 
Jan 7, 2007
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HI
It can be done as I had the upgrade done on my 2016 X5 by my local towbar specialist in Basingstoke, Hampshire. First Direct towbars. Ask for Mark Copeland who is the owner. Number is 01256 811801. He's done all my cars, they're excellent.

They connect to the spare pins in the electric point so it's completely seamless and hidden. Cost about £160 from memory.

Brian
 
Oct 8, 2006
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steve2019 said:
you could do this yourself if you are competent with wiring, the question would be whether you have cables attached to pins 10 and 11 (the positive and negative terminals for the fridge) even if they arn't connected to anything in your car.
if you do and can locate these cables then pin 11 is your earth (connect to earth in your cars boot area) and pin 12 is live but ONLY when the engine is running, this is important because if you hook it up to the battery so it's live all the time then yes the fridge will work, however if your cars battery goes flat for whatever reason then it will try to crank the engine from the leisure battery as it is hooked up to the same live circuit...and you don't want 120 amps running through those cables..they will melt at the very least...and catch fire at worst.
this fridge live wire should also be fed via a relay (any basic 4 pin relay is ok) and obviously through an inline fuse (20 amps should be ok)
I recently wired a 13 pin tow socket into my bmw, but didn't use the cars own wiring harness for it, I bought my own relays and canbus unit which worked out a lot cheaper and easier to install.

Er, correction.
Pins 10 and 11: pin 10 is live but only when the engine is running; pin 11 is earth but it needs to be a good chassis earth with a good sized cable and preferably as short as possible.
Pins 9 and 13 are the permanent live on 9 and also earth on 13. Same comment about the earth cable
 
Jan 3, 2019
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ahhhhh...yes sorry, my mistake, I did say 10 and 11 but later in the post typed 12... ( I do know how to confuse things lol)
well spotted Woodentop :)
 
Dec 13, 2017
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I fitted a towbar to a 2008 5 series so likely the same generation can-bus wiring. If all your lights are OK, the simplest option would be to put a split-charge relay in to drive the fridge. Simply puts a heavy-duty 12v supply out on the fridge pin when the engine is running and turns it off when the engine is off. It switches based on teh voltage of the battery. Usually c12v when engine is off and c13.8 when the engine is running. Can cycle on and off a bit if you have a stop/start engine set up but when driving along it'll be fine.
If the battery is in the back same as the 5 series, you need a couple of short runs to the relay then a chunky wire to the fridge pin on the socket. May have to upgrade the earth to the socket too f that has not been provided with enough oompf to provide for a fridge. Won't mess with anything else and the car systems need know nothing about it. This is an example of the sort of relay you need.... https://www.towsure.com/self-switching-smart-split-charge-relay-for-towbar-electrics
 
Nov 6, 2006
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Agree completely with Mark. BMWs generally have the battery in the boot, and often a fuse box too. If you car has a battery charge control system on top of it there will probably be a couple of live terminals apart from the main one, as a power source for the fridge relay.
 
Aug 26, 2014
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I've had this with my last two X3s - we didn't know about the problem with the first until we hitched up. Cue discussion with dealer, who reluctantly agreed to pay 50% of the work required. The latest X3 was into the workshop direct from the factory for the work. The main problem was that the plug didn't have the required pins, and wouldn't accept additional pins, so it was a complete new loom! BMW UK are completely disinterested and as much use as a chocolate fireguard with this issue - which is a pity because it's brilliant towcar, and equally just as brilliant day to day solo.
 
Jun 11, 2012
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Hi Topaz Man Now I have a BMW X5 its a 2001 . I suggest you check in the back of your X5 and find the wiring block for the lights etc. BMW do not put the wiring in for fridges .Now this is quite simple if you find the block you will see a spare terminal that you can use . All that is required if its the same as mine a SPOT LIGHT Relay.
Deli Dave who posts on here did mine for me , took about ten mins and a couple of quid for the relay and of course a pint for wiring it in .
Sir Roger.
 
Nov 16, 2015
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SirRogerFFS said:
Hi Topaz Man Now I have a BMW X5 its a 2001 . I suggest you check in the back of your X5 and find the wiring block for the lights etc. BMW do not put the wiring in for fridges .Now this is quite simple if you find the block you will see a spare terminal that you can use . All that is required if its the same as mine a SPOT LIGHT Relay.
Deli Dave who posts on here did mine for me , took about ten mins and a couple of quid for the relay and of course a pint for wiring it in .
Sir Roger.

Hyundai fitted my tow bar from new, to my Sante Fe, on first hook up nothing to the alko ATC, they hadn't fitted a separate earth back to the car. 20 min underneath the car and all sorted out.
 
Jun 11, 2012
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I appreciate this thread is now dated somewhat but just to clarify the x5s from 2001 up to 2006 were the same . Mine has a factory fitted tow bar and was so easy to fit the wiring to the fridge. The wiring block for he lights etc are in the boot where you find a spare terminal . All that is needed is a spot light relay alive to the relay and from relay to spare terminal in the block then from the block to plug but just cant remember terminal number on plug .
Sir Roger.
 
Jan 18, 2017
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It took some months to arrange, but I've had my BMW X5 wired by Mark Copeland at 1st Direct in Basingstoke for fridge and battery charging. He's brilliant! Knew what he was talking about, got the parts in, arranged for the work to start as soon as I arrived from Essex and had me on my way home within 1.5 hours. All works perfectly. Highly recommended. Thanks for putting me onto him.
 

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