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Discussion Starter #1
I recently installed a trailer hitch on my 2006 9-5 wagon and am now looking to install the wiring for some trailer lights. I've read the posts about the older 9-5's having the wiring harness in the rear hatch area, however, because mine is a later model, it didn't come with the 10 pin connector. I'm wondering if anyone has any information on the wiring for these models. I'm nervous that splicing the tail light wires to install a typical wiring kit will cause rear light error messages on the SID or that my parking sensors will constantly beep if there is a trailer behind me. Any help is appreciated.
 

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Last time I checked at a Canadian dealer, that piece of harness was ridiculously expensive, maybe $200 or more. The other problem is that North American trailers use a simple four-pin connection and you will have to use some kind of converter anyway.


If you get a powered adapter module, you can poke the various trigger leads into the back of the appropriate socket where the wire for that bulb goes in. Then you have to find a constant-on +12V source to actually power the module.


We had a discussion less than a year ago about this, but I can't find it at the moment.
 

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So essentially I wouldn't have any problems using an off the shelf converter and taping in the existing wiring? Not sure if there's any benefit for me to install the pre-tow wiring if I will need to splice into the wires anyway.
 

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Dig the little plug out of the rear harness and tap-in a stop-lamp or indicator bulb to the various terminals (one at a time find an earth then a feed wire). If the car will run the bulb correctly without throwing the rattle out of the pram it'll be fine - what you're looking for is full CAN-bus integration which I doubt the 9-5 OG has (at least for the rear lights to trailer). Mine hasn't, I have a generic by-pass relay that's about £25 and will work fully and well in any non-CAN-bus car.
 

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So essentially I wouldn't have any problems using an off the shelf converter and taping in the existing wiring? Not sure if there's any benefit for me to install the pre-tow wiring if I will need to splice into the wires anyway.
I would use a powered one. Those use the different light inputs as triggers only. The module switches on whichever light using its +12V power supply.

The passive or unpowered modules tap the power going to the car's lights to power the trailer lights. The unusual current flows might give you light warnings.

The trick to using the powered module is to find a constant +12V source with sufficient amperage to power your trailer's lights. LED tail/stop lamps are really helpful here. A basic trailer with LED tail and side lamps is probably fine with a 5A circuit. I ran my basic utility trailer with bulbs for years off a 5A tap to the power antenna lead in my NG900 with no issues.
 

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Discussion Starter #8
Just wanted to update this post to confirm that the powered trailer wiring kit works perfectly without causing any bulb errors to the SID. The kit I used can be found here
 

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I just ran a cable from the battery since that's what the guild from CURT recommended to do. I used this just because that's what the guild recommended and it should keep everything protected with the fuse.
 

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FYI, I installed this kit today in my 2006 wagon, and documented my work in this post: large format paper wiring diagram?

I'm cross-posting it here because that thread isn't where somebody would necessarily look for detailed information on wiring up trailer converter in a 2006 wagon...and this thread is!

Thanks to everyone who's posted great useful information here in the past.
 
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