where's the tow harness?

mjginsrq · #1 03-16-2011, 09:49 AM

have a 2006 X5 with an aftermarket class A hitch and I can't seem to find the wiring harness. have looked under and see nothing. in the spare tire compartment I see something that might be what i'm looking for. it's a black square receiver but looking nothing like any towing wiring assembly that i've seen. will try to get a pic but in the mean time if anyone has an idea or suggestion, it would be appreciated. thanks

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Lookin4Trouble · #2 03-16-2011, 09:59 AM

wierd, my tow harness was tucked up under the rear bumper cover on the passenger side zip-tied to the PDC sensor wiring. Just had to cut a zip-tie and pull it over to the tow hitch area...

TowX · #3 03-16-2011, 11:18 AM

The connection for the factory towing module is in the spare tire area. There is no harness per-se, just a plug to hook the factory module into.

JCL · #4 03-16-2011, 12:13 PM

Near the battery is the plug in the vehicle wiring harness that accepts the tow module (white box in the picture below). The trailer harness (shown below) plugs into the white box, is led out through a grommet, and is mounted to the receiver with the supplied bracket. All of this is a kit that is supplied with the OE hitch, but which you can purchase separately if you have an aftermarket hitch.

See this ECS tuning link (also available at your dealer):

BMW E53 X5 M54 3.0L > Exterior > Trailer > ES#185391 Wiring Harness - 71600009698

tonytsai0429 · #5 03-22-2011, 05:18 AM

Hi JCL,

thanks for the pointer!!

finally i got it done, my tech were great finding problems and solve them at the same time, PM'd me if anyone in SoCal needs help.

Now, do i just buy the cable pin adaptor or the whole kit as in your picture? seems to me the adaptor has those pins that looks like i can just buy them from Pep Boys down the street...

, no?

TowX · #6 03-22-2011, 07:16 AM

You need the entire harness as shown in JCL's post. This will put the 7 pin round connector next to the receiver. You would use the adapter you've pictured to plug into the 7 pin round and adapt it to the 4-flat plug you have on your trailer. I use one of those adapters too when pulling the jetskis or a small Uhaul trailer. But the harness set you get from BMW includes the correct plugs to plug into your vehicle's wiring harness without butchering it up, and it has an electronics box as part of it which really makes everything work right. Remember, the wiring in an X5 is hall-effect, in other words some of the wires in the system do more than one thing, and the light control module in the right front foot well controls the pulsing of the signals through the circuits. It's very easy to muck it up.

BTW- nice looking setup- white X5, white bike, and even a white trailer. Nice.

JCL · #7 03-22-2011, 12:31 PM

As Towx says, you need the entire kit with the trailer wiring box, the harness, and so on.

However, if you already have that kit, and are just missing the adaptor that you attached a picture of, that goes from round to flat 4 (for a small trailer) then any trailer supply shop, or U-Haul, sell them for a few dollars.

tonytsai0429 · #8 03-22-2011, 07:08 PM

thank you thank you, don't know what else to say...YOU GUYS ROCK!!!

for ordering the adaptors, online is better or just run down to my dealer would be easier? anyhow, let me call them to check if they have any in stock

tonytsai0429 · #9 03-22-2011, 07:49 PM

Quote:

Originally Posted by TowX

BTW- nice looking setup- white X5, white bike, and even a white trailer. Nice.

LOL,

didn't even notice till you pointed out...

TowX · #10 03-22-2011, 08:54 PM

Quote:

Originally Posted by tonytsai0429

thank you thank you, don't know what else to say...YOU GUYS ROCK!!!

for ordering the adaptors, online is better or just run down to my dealer would be easier? anyhow, let me call them to check if they have any in stock

I bet a well stocked UHaul store has them. But personally I get a lot of my trailering stuff from the guys at etrailer.com:
Pollak 7 Pole to 4 Pole Connector Adapter Pollak Wiring PK12716

And if you have LED lights on your trailer causing your blinkers to flash too fast:
7-Way to 5-Way and 4-Way Trailer Adapter for VW, Audi and Porsche Towing Trailers with LED Lights Valley Wiring V39008

The folks at etrailer are great to work with and after probably 7 or 8 years getting things from them they've never failed to impress me with their knowledge.

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