Product review: Repro tow hitch wiring

Bdc101 · #1 05-04-2021, 10:32 AM

I just wanted to report my experience with this reproduction product. An ebay seller "bahgellson" is making trailer wiring harnesses for use with the factory towing module (AHM), which have been out of production since before I bought my E53 in 2016.

https://www.ebay.com/itm/324580444572

When I bought my E53, it had a factory Westfalia hitch (improperly installed) and it had a seven-pin wire connector which I found was wired up to a Hidden Hitch wiring module that had been spliced into the brake lights. Since we are trailer campers, I fixed the hitch, added a brake controller, but could never find a used wiring harness for use with the AHM module. The modules themselves are all over ebay in the $60-80 range, but the wiring harnesses are few and far between. Anyways, I was glad to pay the $190 for this repro harness with the new dual trailer plugs.

I installed it this weekend and found that it was plug-and-play. No coding was required on my 2003 (11/2002 production) which is a pre-facelift car. I did have to remove the bumper cover to fish the wires through, as there was no way at all to do it without removing the bumper cover. I also had to trim about an inch off the bumper cover to fit the dual trailer plug, and drilled another hole in the hitch to screw it on. However, it ended up looking fine; since it's kind of tucked in underneath the bumper it's hard to notice. My E53 isn't a garage queen like some of yours either

I did have to buy another pin for the trailer brake controller wire, and I haven't wired that up yet, but the seller was helpful in identifying which pin to buy and it can be crimped with a normal automotive crimp tool.

Overall I was very happy with the purchase. Now, I don't get the light alarms on the dash when I plug in my trailer, and I can charge it while towing, and the lights are actually brighter than they used to be (probably because of the crappy aftermarket splices). Just wanted to give credit where credit is due. I'm glad to see someone making reproduction parts for our cars (and also E83s, apparently).

(Sorry no pictures -- I don't have a smartphone)

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Leghab · #2 05-04-2021, 11:01 AM

Really appreciate you taking the time to make the review!

Like you, I bought a 6MT 3.0 a few years back. At the time, the only way to use the actual BMW method of trailer lighting was to either hope you get lucky in a junkyard (which was becoming ever-less-likely) or pay $400-500 for someone's old harness.

So I built my own and decided to sell them as well.

If anyone has questions on how to install this harness - or how to make it work with a brake controller - I am more than happy to answer them.

The Sterlingfrau is currently at the shop suffering from the effects of a botched clutch replacement, but once I get it back, I will make an installation video to show the trick to installing the harness without bumper cover removal.

P.S.: It's me, the seller

Bdc101 · #3 05-04-2021, 12:23 PM

Great to hear you are on the forum. I'll see if I can get a picture uploaded, but when I've tried in the past it was nearly impossible to get the pictures sized correctly and uploaded.

wpoll · #4 05-04-2021, 04:11 PM

Quote:

Originally Posted by Bdc101

Great to hear you are on the forum. I'll see if I can get a picture uploaded, but when I've tried in the past it was nearly impossible to get the pictures sized correctly and uploaded.

Load your picture(s) to imgbb.com and past the BBCode Full Link link here. easy.

Bdc101 · #5 05-04-2021, 04:26 PM

Quote:

Originally Posted by wpoll

Load your picture(s) to imgbb.com and past the BBCode Full Link link here. easy.

I don't generally like to use free hosting sites -- they have too much spyware/adware/trackers. Imgur is the only one I have used in the past.

The free hosting on this forum is fine, except I have to go and download and resize my photos every time because it won't do it for you.

Effduration · #6 05-05-2021, 09:22 AM

Those dual purpose 7-way/4-way connectors are practical, but I'd rather not cut the bumper cover that way. I think will stick with the 7-way connector and use a plug-in adapter (bullet) when I need a 4-way.

Bdc101 · #7 05-07-2021, 10:56 AM

I agree, but I was happy to get the one I got. Good feedback for the seller though. I will probably trim that up and make it look a little nicer. The extreme rake of the bumper in that area makes the shape of the required hole look funny from behind the car. If I cut it a little more and it will look a bit nicer.

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