BMW X5 E53 DIY OEM Hitch Installation Notes and factory installation PDF - Page 14

Riggodeaux · #1 05-19-2014, 07:20 AM

I finally installed the OEM hitch this weekend that had been sitting in the garage since December. Some key additional points and one question:
1. When installing the two bumper brackets [item f, #8 in the 'D' diagram in the BMW .pdf], make sure the 'long' sides point down! otherwise, the bumper cover won't fit where it meets the tailgate! Lining up those two T55, M10x85 bolts is a pain, but you can reach the T55 heads with a 'wobbly' extension on your 3/8" socket drive, lying on your creeper and looking up at the bumper.
2. When removing the original bumper, remember to leave on the two plastic caps on either end, so you can see how to fit them on the new bumper. Counterintuitive. Their function appears to be to divert rain/spray draining down the back away from the bumper innards.
3. When reinstalling the new bumper [with the end caps and cover attached], aside from 1., you need to angle the cover in the get the caps under edges of the rear corner panels, then line up the plastic clips inside the outside corners with the slide-in clips behind each wheel well, and the top of the bumper on top of the two 'verticals' on the bumper brackets. As Ed on 'wheeler dealer' sez, it really helps to have two for this function.

If you don't miss-mount the two bumper brackets and err by taking off the two end caps, this is a 4 hour job with two guys, even with the tedious job of removing all the plastic punch-pin clips.

And my electronics question. The kit comes with an electrical module [p, trailer module AHM II, shown at 19 on diagram H, and in the Circuit Diagram as X609. It mounts under the spare over the battery. Iits installation is described at 2.4, E-H of the BMW instructions. What is its function?

Finally: While doing all this, make sure you view and copy the bluetooth code from the 'motorola' white box on the rear left side. Easier to see when you have taken everything out of the cargo area ...

Riggodeaux · #2 05-19-2014, 07:23 AM

One more point, going to the earlier issue raised about the hex heads not fitting the locking indents in the bumper brackets: mine did fit, though you needed to tap them in to lock with a hammer. You then tighten to 50ft/lbs 65nm on the nuts from inside the cargo area.

LVP · #3 05-19-2014, 08:07 AM

Hahaha - I'm in the process of doing the exact same project. Got it all torn down last night. Today is re-assembly. The only thing that helps get through it is knowing what the end product will be like

Thanks for the tips - very timely…

I believe the module activates the wiring harness when something is plugged in and disables the park distance control when a trailer is plugged in. I doubt the harness will work correctly without it plugged in. From what I have been told by a few people and the parts guy at the dealer, this is a plug and play solution that won't require programming. I'll know by Thursday when I can actually get it down on wheels and plug into a trailer.

Riggodeaux · #4 05-19-2014, 08:29 AM

Good luck, LVM! The OEM hitch kit is very well-made [by Westphalia in Tennessee, it appears], and everything fits together very well, though close tolerances, and you have to fit certain things together all at the same time to install. I expect you are right about the plug-in X609 trailer module. If you have the backup warnings, you already know to be very careful when taking off the old bumper to unplug the wiring harness inside the cargo area and at its rubber grommet so as not to pull the wires out of the sensor unit(s). Note the kit comes with a warning sticker about 'no brake controller', to be added to the hitch if you don't have a controller; note also the rec'd limits on length/height of the hitch ball/shaft in the OEM instructions. I'm still leaning toward the RF version of the Tekonsha Prodigy brake controller, which requires not wiring in the vehicle, as we'll be moving the controller between my X5 and the CEO's Mercedes diesel ML .....

TerminatorX5 · #5 05-19-2014, 09:02 AM

Hey Riggo... The AHM module is an extension of the LCM module, it provides the lighting solutions for the trailer lights (non-LED), and when the trailer lights are connected, the AHM will disable the rear PDC if so equipped, will disable the manual operation of the 4-corner ride height control, if so equipped and will disable the rear fog lights if so equipped, or if wired properly through the LCM and not via the trailer module (see the rear fog threads on this forum). The AHM will not provide the brake control, but you already know that...

If your trailer has LED lights, you can get yourself a 7-pin to 4-pin converter (the US plug is 4-pin), and solder in three resistors that will act as additional load for the AHM to make it think that there is an incandescent light bulb - also is helpful to have the 7-pin-to4-pin adapter with resistors if you hook up a basket or bicycle carrier, the adapter will cut off the annoying rear PDC...

you can see the adapter in my thread referenced in my signature...

Congratulations on the install!!

Riggodeaux · #6 05-19-2014, 09:08 AM

Thanks Terminator, that's what I figured on the X609 AHM Module. I have a 7-4 pin converter, but the added resistors in it would make sense to cut off the annoying PDC if I find myself carrying a hitch box.

JCL · #7 05-19-2014, 12:28 PM

The trailer module essentially tells the vehicle a trailer is there if the harness is connected. In addition to the features mentioned, it enables the vehicle to use the Trailer Stability Control mode of the DSC. I've never had TSC intervene, even towing on snow covered roads, but it is nice to know it is there.

Depending on your vehicle date of manufacture you may require coding to get the vehicle to recognize the trailer control module. That started with vehicles built from 2004 onwards IIRC.

Riggodeaux · #8 06-11-2014, 04:59 PM

Quote:

Originally Posted by JCL

The trailer module essentially tells the vehicle a trailer is there if the harness is connected. In addition to the features mentioned, it enables the vehicle to use the Trailer Stability Control mode of the DSC. I've never had TSC intervene, even towing on snow covered roads, but it is nice to know it is there.

Depending on your vehicle date of manufacture you may require coding to get the vehicle to recognize the trailer control module. That started with vehicles built from 2004 onwards IIRC.

JCL, Terminator, after installing the module, I'm getting intermittent 'check brake lights' and 'check rear lights' messages on the dash display. Both appear to be working. I'm assuming this is an indication I need to visit a dealer to get coded. What think you?

JCL · #9 06-12-2014, 12:50 AM

If the module is recognized by the vehicle, the rear PDC will not engage when a trailer is connected. That was my standard test.

If you are getting error messages with the module and before a trailer is connected, I would try coding it.

If you are not getting error messages with the module and no trailer, but then do get errors when a trailer is connected, I would check to see if you have LED trailer lights and if so use an adaptor.

I would expect to have to code a 2006 model

TerminatorX5 · #10 05-19-2014, 12:33 PM

I had the trailer set up on 2002 4.6 and then i transferred the same set up from '02 to the '06 4.8, all the same inner hardware and electronics. I did not code though...

I used the hitch for the bicycle rack and the basket - both with the 7-to-4-pin adapter with the resistors (maiden voyage was without resistors, and the turn signals were acting up, they would blink normally, and then blink fast as if bulb was blown - the adapter had built-in LEDs that threw off the LCM. Once I fitted resistors, the light mayheim stopped).

But, I did not tow a real trailer yet, so maybe I do need some programming...