Draw-Tite Tow Hitch Install Notes

[kcheves]

BMW X5 trailer Hitch Install Notes

I have completed the installation of the Draw-Tite Class 3 trailer hitch on my 2013 E70 x35d. There are some good threads on this, but I wanted to pass along a few lessons learned from my install and elaborate on points not addressed in the DIY threads or the OEM installation instructions. Sorry in advance for the length of this post.

1. Parts used. I sourced the Draw-Tite Hitch from www.etrailers.com, and the OEM wiring harness from www.mybimmerparts.com (Passport BMW in MD). I chose the Draw-Tite over the other commonly available 3rd party hitch made by Curt because a) it was recommended on several of the DIY threads, and b) the Curt Hitch warranty requires you to use straps when attaching anything but a flat trailer to the 2" square receptacle. No thank you, Curt.

2. Instructions used. BMW installation instructions for the trailer kit, P/N 01 29 0 412 716. There are several versions of this on the interweb, with the older versions lacking important detail on the wiring pass through. I used Version 5.0 dated 8/2009, which was written for LCI cars. This instruction covers the installation of both the OEM hitch (which I didn't use) and the OEM wiring harness. It starts with "Remove bumper fascia" without telling you how. The www.etrailer.com installation video covers this well but does not address wiring at all.

3. Removal/Re-installation of the rear bumper. You will need an assistant for this part of the job. Getting the rear reflectors out is probably the hardest part. Once you get the first one out, the other side is easier. Substantial force is required to pull the bumper cover free on the sides. You really need to reef on it with two hands, as shown in the video. On my 2013 (one of the last E70's built in 6/2013) I did not need to remove the tail lights. YMMV. The PDC harness disconnect (a single connector beneath the right hand side of the bumper) is hard to see, but can be separated after the bumper is removed if you are careful. The latches on the side of this connector are fiddly and were easier to access once the bumper was off. Re-mating of this connector is possible after the bumper is re-installed (this is how I did it) but is made more difficult by the proximity of the newly installed trailer hitch. This connector is keyed but the keying feature is difficult to see. Note the direction the harness wires bend when you take the connector apart. On my car, the wires had taken a "set" in one direction, but the correct orientation was 180 degrees off. You will get a PDC error when you shift into reverse if you do it wrong.

4. Installing the hitch. The impact bar under the bumper must be removed before the hitch can be installed. This part is discarded if you install the OEM hitch. For the Draw-Tite, you install the hitch and then re-install the impact bar on top of the hitch. The etrailer video has an error at the point where they re-install the impact bar. They show the upper edge of the impact bar being installed partially under the black plastic piece that runs side-to side above the impact bar. You need to tuck the impact bar *completely* under that plastic piece, or the plastic piece will deform and make it impossible to install the bumper cover. This deformation is clearly visible when they tighten the top nuts in the video. I sent them a comment on this so they can update their instructions, and I'll update this thread later with some photos that show this clearly. There are black plastic caps on the 4 top bolts (2 per side) that attach the impact bar and are visible when the lower hatch door is open. Because the exposed length of the stud is reduced with the Draw-Tite installation (due to the stacking of the impact bar on top of the Hitch), these covers no longer press into place. Per the etrailer instructions you must fill them with RTV and smoosh them on, which is the hokiest part of the installation. I think you can do this as the last step once everything is put together, which will save you from a goopy mess if you need to remove and reinstall the impact bar, as I did.

5. Wheel well arch rivets. I purchased 6 replacement OEM single-use poly rivets from my stealer @ $2/each, but the poly rivets included in the Draw-Tite kit would have worked fine. I also purchased the rivet tool from the Chinese Embassy, which comes with an assortment of rivets, including the size you will need. The rivet tool is larger than I expected, and access in the wheel well is tight. Removing the rear wheels would have helped, but I was 4 hours into this 2 hour job, the PGA final round was playing, and I had a powerful thirst.

6. Cutting the bumper cover. The Draw-Tite instructions state that a 2" x 8" section on the bottom of the bumper must be cut away to prevent interference with the hitch. The bottom of my bumper cover was pre-cut from the factory, and no additional cutting was necessary. This was a nice surprise. I looked up the part number in BMW Parts Catalog, and it looks like a change was made during LCI production to add this detail to the bottom of the bumper cover, and the factory cutout (if you have one) is easy to see if you look under your car. Mine is about 3" x 13", which easily accommodated the Draw-Tite hitch.

7. Installing the wiring harness. There are two wiring access holes on the right side of the car between the rear bumper area and the fuse panel that is in the rear cargo area. The inboard hole must be used for the OEM harness wires, and the instructions state that if you have PDC and Comfort Access the inner hole will probably be taken by the Comfort Access antenna. In my car, the inner hole was vacant and had a rubber plug, making the install easier. Please, no jokes about inner holes with rubber plugs. BMW must have changed the vehicle wiring harness at some point to put both PDC and Comfort Access cables through the outboard hole. As a result, there was no need for me to disconnect the Comfort Access antenna and move it, and the connectors on the OEM harness for tying in the Comfort Access antenna thus went unused. With the exception of the 7-pin connector and the Comfort access connector (unused in my install), the rest of the harness needs to be fed through the inner access hole from the rear of the car into the fuse panel area. The only challenge with this is the 16 pin connector that mates with the provided AHM module. You will need to remove the locking lever from this connector to pass it through the wiring access hole. Be careful not to break this dainty clip once removed - ask me how I know. There are a number of oval clips at fixed locations on the harness that plug into corresponding oval features built into plastic cable tie points at the rear of the car. These are used to secure and strain relieve the tow hitch wiring harness. The Draw-Tite hitch is different enough from the OEM hitch that most of these restraining points do not line up once you route the wiring harness. Instead, I used cable ties where needed.

8. Mounting the 7-pin connector. The harness terminates in a female connector which mates with a provided detachable 7-pin RV connector with a hinged cover. This appears to be a stock Pollack part. It would be nice if there were a compatible detachable connector that included a 4-pin flat connector, but I could not find one that was not pre-wired, and I was unwilling to splice into my new $200 wiring harness. Speaking of which, I'm over my initial shock that the wiring harness is more expensive than the hitch. The harness is really well made, and includes everything you need. If this were a Porsche harness, it would be $600 . One nice touch is an included 7-pin to 4-pin adapter. These are available on Amazon for $7, but it's one less thing to buy. The OEM Hitch has a metal tab welded to it where you can mount the 7-pin connector; the Draw-Tite Hitch does not. You will need to purchase and install a right angle bracket for this, they are widely available.

9. Other thoughts. I chose the Draw-Tite Hitch because I liked the way it looked and didn't want to cut into my bumper cover. The www.etrailer.com kit and their video made this installation pretty straight forward, maybe a 5/10 in difficulty. In retrospect, I would probably get the OEM hitch for about the same price. I think there is some value in keeping the installation OEM, and some of the features built into the OEM Hitch are nice, such as the mounting tab for the 7-pin connector, the ability to use the included strain relief points, the elimination of the impact bar, and no need for RTV to attach the upper mounting stud covers. Those are nits though, the DrawTite Hitch is well made and will serve me well. The OEM harness is really nice and no wire splicing is necessary unless you want to connect the optional trailer emergency flashers. The splices for this are included in the kit if you are so inclined, I was not. It's also nice that it is pre-wired to connect a trailer brake module, which is optional and not included.

I have not completed the integration of the harness into the fuse panel or the coding to add the new AHM module. I ran out of time and am saving that for another day. The price I was quoted for remote coding is about $200, so I'm reading up on NCS Expert and will attempt to do this myself. I could probably live with the annoyance of the PDC sensors beeping when in reverse when towing a trailer, but my understanding is that coding is required if you want the trailer brake lights to function properly.

I'm taking pictures as I go, and will update this thread when I'm done.