 | Home > Off Topic > Fitting 13 Pin trailer electrics to a Merc |
 
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| TexasRover Member Since: 24 Nov 2022 Location: Paris Posts: 794   
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Looking at the same for my beemer some months ago and it looks like most modern car rely on the network in the car (canbus) to provide the light signals and rather than tap into the existing bulbs you buy a little gizmo that you connect the canbus (and power) and it will switch on the relevant build in relays and supplies the power to the socket.
For most cars you can buy this aftermarket including the correct connectors to plug into the wiring harness. For the Beemer no programming is required, but although I bought the kit, I have not fitted it yet |
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12th May 2023 7:44am |
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| Bluest Member Since: 23 Apr 2016 Location: Lancashire Posts: 3997  
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Thanks, can you point me to the item you have so I can do some research? 2007 110 TDCi Station Wagon XS
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12th May 2023 9:02am |
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| rallysteve Member Since: 10 Feb 2014 Location: Cumbria Posts: 2199 
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If you use a vehicle specific kit then the car will need programming, there is no way around it if you are doing it properly. My 12yr old Audi needed both Engine ECUs, Transmission ECU, ABS ECU and instrument unit programming to correctly work with the factory towbar module which I retrofitted.
Have a look on here: https://www.pfjones.co.uk/ Often you can download the instructions for the electric kits which show you where they connect and often (at least in the case of Westfalia/VAG group) also give you a clue as to which modules need coding. Steve 02' 110 TD5 Double Cab Rebuild Thread 84' 90 3.9 V8 Caged Pickup Build Thread - Now For Sale Mobile Diesel Heater Build Thread |
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12th May 2023 9:07am |
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| lohr500 Member Since: 14 Sep 2014 Location: Skipton Posts: 1285 
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[rallysteve beat me to it in suggesting you look at the PF Jones website.
I think this is the correct wiring fitting instruction, but do check yourself to be sure : https://www.pfjones.co.uk/pfjoneswiringkit...ctrics.pdf Note drawing 30. If the Mercedes SAM module in the rear of the car doesn't have the relay shown, then it looks like you will also need the optional wiring kit for pin 10 which will involve running a separate live feed from the battery. Trailer wiring was a lot easier in the good old days!!!![/i] |
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12th May 2023 9:30am |
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| Bluest Member Since: 23 Apr 2016 Location: Lancashire Posts: 3997
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I'm beginning to think I might offer to fit the bar, but tell him.to get the electrics sorted by a pro. 2007 110 TDCi Station Wagon XS
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12th May 2023 2:29pm |
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| Procta Member Since: 04 Dec 2016 Location: Sunderland Posts: 4937
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if there is a plug and play kit for it, your pal can buy a decent diagnostic kit from amazon that could be worth looking at, One of the lads i am subbed to on youtube did a video on it, which covers a lot of the later stuff, I am looking at buying it for my peugeot 306, so this may help with the programming side of things.
https://www.amazon.co.uk/XTOOL-Automotive-...B0BFFXBTDJ Defender TD5 90 ---/--- Peugeot 306 HDI hatch back Success is 90% Inspiration and 4 minutes Preparation # you can make it! |
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13th May 2023 2:12am |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3208  
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Anyone tried to just tap into the respective power cables for brake, side, indicators etc, and use LED bulbs on the trailer? LED with their very low current hopefully not detected by the can bus? 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black |
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13th May 2023 6:37am |
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| TexasRover Member Since: 24 Nov 2022 Location: Paris Posts: 794
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I think that might work, but you don't know what will be plugged in in future and these body control modules are worse than your wife.
Possibly just a few relays might do the job? You need to decide what you want because the manufacturer has invented all these unnecessarities which require all this programming, while really what you might be after is just a few lights. Looking at the various aftermarket suppliers there are fancy and more basic packages. I am mildly amused by the desire the switch off the rear parking sensor (there is button for that), but reprogramming the gearbox and ABS to tow a trailer? Really what are you going to do? go cross country in the snow? Surely anybody will know that when a tow a trailer there are some basic considerations towing and if you don't get that maybe you should not be towing. There are probably cars out there now that have a 'self reverse park WITH caravan option' My Td5 110 basically just has an extension lead, works great. |
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13th May 2023 9:02am |
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| rallysteve Member Since: 10 Feb 2014 Location: Cumbria Posts: 2199
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You would be surprised what differences there are. Engine ecu's on mine control the switching point of the electric cooling fans and the electronic thermostat as well as the control of the alternator charging.
The gearbox holds onto gears for longer whilst towing and modifies the lockup point of the torque converter. Abs module modifies the stability control and rear brake force distribution to account for the weight on the towbar. It also plays a part in the response of the cruise control which is more subdued with a trailer. The car also monitors the function of the trailer lights and warns you if any stop functioning. Depends what you are towing, i tow upto the 2tonne limit with mine and like to know everything works as intended. If you are towing a little unbraked camping trailer then fine. The 'CANBUS' stuff is largely rubbish. Its the bulb failure monitoring system which will be compromised by using a bypass relay. You may also find it ends up sequentially strobing the lights on the trailer of they are LED as that is how the system works. I know a number of fords will also rapidly flash the indicators if you connect a trailer into the circuit (what it does when you have a bulb out) You could look into using a direct canbus module which will read some if not all of thr lighting signals. I have never looked in detail at using one but i am sure they are available 02' 110 TD5 Double Cab Rebuild Thread 84' 90 3.9 V8 Caged Pickup Build Thread - Now For Sale Mobile Diesel Heater Build Thread |
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13th May 2023 2:41pm |
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