Hello, I have a European trailer wiring harness setup for their 7 pin round connector (ISO 1724, plug looks like our round plug but wired differently) and I want to put a NZ flat 7 pin plug on the end of it.
Most of the pins are obvious but I am a bit stuck with the correct thing to do with the two tail light wires, they use one pin for the left tail light and another for the right. (where we just use one pin for tail lights). I am reluctant to "have a go" and just use one of the tail light wires or bridge them as this isa proper dedicated wiring harness that has an box which interfaces with the cars CANBUS system.
My thinking is if I use just one of the tail light feeds at best I will probably geta bulb out warning on the dash and at worse I might damage something with the increased current draw.
Likewise I am reluctant to bridge them for similar reasons.
Anyone have a difinitive answer as to what is the safe/correct method of changing to the NZ 7 pin flat plug!
Yeah nah, those just convert the pins as wired which won't help the issue as while the plug is likely the same as NZ the wiring is not. Thanks for the thought though.
The more I think about it the more I reckon bridging the two tail light wires together would be the correct thing to do. My thinking is this will not place greater than expected current on either circuit and because there will be some resistance showing the bulb out warning indicator should not show.
BUT. I didn't get much sleep last night so having a VERY slow brain day and would hate to damage an expensive car and/or harness.
Keep the ideas coming!
thejazzpianoma,
Feb 4, 7:51pm
For what its worth here is the NZ Plug wiring for both round and flat plugs:
1. Left hand turn 2. Reverse (if fitted) 3. Earth 4. Right Hand Turn 5. Service Brakes (If Fitted) 6. Brake Lights 7. Tail Lights
U.K/International Standard Wiring 1. Left hand turn 2. Fog Lights 3. Earth 4. Right hand Turn 5. Right hand Tail light 6. Stop lights 7. Left hand Tail lights.
My thinking is. If I bridge the right and left tail lights by putting wires 5 & 7 in to pin 7 that should be the correct thing to do (so long as it dosn't damage or upset the car). That would leave the service brakes pin blank (which would be optional anyway) and if we fit a fog light to the regular trailer towed then there should be no bulb out warning light. In the event someone else's trailer is towed the worst that can happen is the reverse lights coming on if someone turns the fogs on in the car. which would only happen if the reverse lights were fitted to the trailer and the driver would be aware of this anyway.
What do you think!
malcordesign,
Feb 4, 8:09pm
The reason for the seperate tail circuits is for the parking lights that noone in NZ ever uses, and if they do they are usually idiots and put the kerbside one on instead of the road side one, I would just hook up to one of them and be done with it.
kazbanz,
Feb 4, 9:17pm
My only concern withjust"she'll be right" and running 2 into 1 for the tailights is if its a modern car with low voltage (led) tailights. I don't know if it will overload the system linking them
thejazzpianoma,
Feb 4, 9:39pm
The catch there is if you just hook to one then the car will think the trailer has a blown bulb. Also, apparently each light circuit is only rated to 55 watts or so which could easily be overloaded if a trailer with side markers etc was hooked up. If only it was that simple.
thejazzpianoma,
Feb 4, 9:42pm
Yes, this is pretty much my concern in a nutshell. Not so much the LED bit as the intermediary box is entirely independent of the cars tail lights (Its a proper dedicated loom that gets its signals directly from the cars canbus system).
But none the less I have concerns about whether there is something I have not thought of that could be bad for the expensive dedicated loom if I try that.
I can of course contact the distributor of the loom but not sure whether they will actually know the answer and I did want to get this job cleaned up a.s.a.p.
fertman,
Feb 4, 9:49pm
My Merc truck has the two tail light wires, and I think it was to do with the fog light circuit.Trailer kis only wired to one and does not throw a code.
thejazzpianoma,
Feb 4, 9:52pm
I have a fog light circuit as well. so I guess that makes 3! I don't think I will get a fault code if I hook just the one up but I am expecting to get a bulb blown code. I will actually be able to try it shortly and see as nearly finished the rest of the wiring.
The loom is supposed to be able to pass on bulb out warnings so pretty sure this will be the case.
skin1235,
Feb 4, 9:56pm
thought about downrating the bulbs,! twin 6w existing could be dropped to twin 3 or 4w, no risk of o/loading the car wiring, side lights are not subject to a lumin test here
thejazzpianoma,
Feb 4, 10:03pm
Good idea, but not my car and its likely to end up towing a hire trailer etc from time to time. Just trying to idiot proof it if possible. Plus it would still throw a blown bulb light up on the dash. Good thinking though.
bigfatmat1,
Feb 4, 10:36pm
what sort of car!
clark20,
Feb 4, 11:03pm
OK, what is done is both wires are run through a diode each and then joined, so power for the trialer and no feedback across the system, keeps the computer happy.
jmma,
Feb 4, 11:35pm
If you wire it as per english one, its still going to power all the trailer tail lights, So just run a wire back into the boot from No5 and fit a light to it (o:
thejazzpianoma,
Feb 4, 11:44pm
* 2005 Audi A3 (same as MK5 Golf) * Dedicated wiring kit (clone of audi one) that takes power and canbus from the front to its intermediary processor which the trailer wires come out of.
thejazzpianoma,
Feb 4, 11:47pm
Yep, thought about that but multiple problems with that one I am afraid. * Unless the bulb in the boot is of equal wattage to the combined lights of every trailer you will likely get a bulb out light on the dash. * Still have the overloaded circuit issue * Possibly might even throw a code for one bulb always being plugged in.
I appreciate the thinking outside the square though.
thejazzpianoma,
Feb 4, 11:49pm
I like this idea a lot!
Are you in agreement as well bigfatmat1!
Now, I am a real noob with regards to diodes, I know what they do but thats about where it ends. So, do I need a specific size etc for the amount of current! Anything else I need to know before heading off to Jaycar!
Cheers clark20 you are the man!
thejazzpianoma,
Feb 4, 11:56pm
BTW, another question. At the front end of the car the trailer loom has 3 wires which hook in to canbus etc and then two with fuses in which I am assuming are 12v power. The instructions show the two with fuses in, which are red with a stripe going to a spade terminal that dosn't exist on thecar.
So. million dollar question. you reckon I am right on those being connected to a 12v source!
My reasoning on this is: * Both are primarily red in colour * The other wires in the loom are clearly not power wires * The box in the back obviously needs power to be run to it. * They both have fuses in the line * Where the wire is supposed to connect to the car is a logical place for a 12v feed (terminal on back of fuse box).
Just trying to be extra safe here as the brain is a bit slow today and it would be a shame to do damage over something stupid.
bigfatmat1,
Feb 5, 12:05am
I just usually use one wire on bmws. Have not done a audi that uses can bus I dont think you have to worry about shorts or overloading as it should have built in protection although the can bus circuit is separate it is protected as well. Just experiment if you not sure if you would like to try diodes 6 amp inline diodes should do the trick. NOt much help on this but in the past just using one wire has worked for me
kazbanz,
Feb 5, 12:55am
Just thinking about it you really dont have a heck of a lot of choice. Somehow you have to make that euro trash electrical system operate kiwi trailers. Given all kiwi trailers are wired the same you must twin the light wire. Thinking further- In theory it makes sod all difference. the juice goes 2 into 1 into 2 -unless Im misinterprettingthe power then runs from car to a common joint and out to two lights.--its not a backfeed . If really worried why not fit a lowwer wattage fuze in each
thejazzpianoma,
Feb 5, 2:28am
Thanks men! I am pretty happy with that, I think adding the Diodes is a good idea even though I agree the loom should be protected. Really appreciate the help.
Tell you what Kaz, that car is such a pleasure to work on. The trim comes off with proper re-usable clips that don't break like the Japanese rubbish ones!
granada,
Feb 5, 2:42am
If you run LED lights on the trailer then with minimun current draw it shouldnt affect anything if you only pick up one wire from the car. You could also wire the two park light wires into a twin relay system to supply a fused 12v feed to trailer plug. This would load both circuits the same and the current draw through the relay windings will be absolutely minimal.Please post what your solution is when you get it sussed
granada,
Feb 5, 3:18am
I know on late model merc 4wd that the factory trailer plug wont run LED trailer lights , You need to get Merc to supply a special adapter at $250 to allow this to happen. Isnt european technology great
clark20,
Feb 5, 3:25am
They usually come from Anything Electronic in Nelson
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