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jsplayin · 03-04-2012, 02:22 PM

I just installed the BMW OEM hitch myself yesterday and it was pretty easy, although time consuming. In case anybody is wondering the BMW hitch is mfg by Thule. I was quoted one hr @ $125 for programming by the dealer, which I will do next week. So diy saved me about $300-600 or so based on what people are posting dealers charge.

I didn't take any pictures since this excellent diy for the execuhitch shows most of what is needed.
http://www.bimmerfest.com/forums/sho...d.php?t=572155

I also used the BMW instructions I linked from bavauto, which is essential for torque specs and fuse locations. http://www.bavauto.com/Assets/inst_pages/ins429.pdf

First you should probably remove the battery, which is sort of a pain but it does provide for some good mental exercise in figuring out how to remove the most over engineered battery attachment system I've ever seen.

I found it nice that the wiring harness is just plug and play, you pull out the existing harness that feeds the parking sensors etc, pop this one in and plug the ends of the old one into this one. I does take some head scratching to figure out how to feed the harness through the trunk opening since the hitch module plug is big and the opening is small. What you need to do is feed the harness starting with this plug first and from the outside of the car feed it in at an angle that will allow it to fit through the hole.

After that the next part of confusion was wiring the fuse box. I suppose I should have taken pics for this since the BMW instructions are confusing as to where exactly the new connectors go in the fuse box. And in case anybody attempts this, the car already has the fuses provided in fuse locations 100 and 145, then you just turn to the back of the panel and the wires go into those corresponding spots to enable those fuses. To install the fuse wiring you first have to remove all the fuses in that plug (take a picture of it before you do this so you know where they go) and pull out the entire plug from the back of the fuse panel. Then the plug has a sort of locking tab on each side, you open that up, pop in the wire, close it and plug it back in.

The only splicing involved was to the blue/brown right tail lamp wire, I was not provided a wire tap btw, so check if you need to purchase one.

The last bit of wiring was just a plug connecting the harness to the pre-wired plug that is taped to the back of the fuse box.

You will also need single use plastic expanding rivets for attaching the wheel arch trim, part #51777171004. I got by with removing only 3 on each side, but it would be much easier to just to remove the entire arches or at least 4 rivets. These rivets require a special rivet gun, since they won't fit a standard riveter as I found out. I'm probably going to have to order one of these http://www.sjdiscounttools.com/mar48000.html to properly attach the trim.

So in summary you would need to purchase to do the job:
1. Trailer kit - Tischer provides new hex bolts and control module holder, other sources most likely don't.
2. one wire tap if you don't receive one with the kit
3. at least 4 rivets and special rivet gun
4. thread lock for the hex nuts - not specified in instructions but prob a good idea

03-04-2012, 02:22 PM	#81
jsplayin Private First Class 32 Rep 146 Posts Drives: F80 M3 Join Date: Oct 2011 Location: Boston, MA iTrader: (0)	OEM BMW hitch DIY I just installed the BMW OEM hitch myself yesterday and it was pretty easy, although time consuming. In case anybody is wondering the BMW hitch is mfg by Thule. I was quoted one hr @ $125 for programming by the dealer, which I will do next week. So diy saved me about $300-600 or so based on what people are posting dealers charge. I didn't take any pictures since this excellent diy for the execuhitch shows most of what is needed. http://www.bimmerfest.com/forums/sho...d.php?t=572155 I also used the BMW instructions I linked from bavauto, which is essential for torque specs and fuse locations. http://www.bavauto.com/Assets/inst_pages/ins429.pdf First you should probably remove the battery, which is sort of a pain but it does provide for some good mental exercise in figuring out how to remove the most over engineered battery attachment system I've ever seen. I found it nice that the wiring harness is just plug and play, you pull out the existing harness that feeds the parking sensors etc, pop this one in and plug the ends of the old one into this one. I does take some head scratching to figure out how to feed the harness through the trunk opening since the hitch module plug is big and the opening is small. What you need to do is feed the harness starting with this plug first and from the outside of the car feed it in at an angle that will allow it to fit through the hole. After that the next part of confusion was wiring the fuse box. I suppose I should have taken pics for this since the BMW instructions are confusing as to where exactly the new connectors go in the fuse box. And in case anybody attempts this, the car already has the fuses provided in fuse locations 100 and 145, then you just turn to the back of the panel and the wires go into those corresponding spots to enable those fuses. To install the fuse wiring you first have to remove all the fuses in that plug (take a picture of it before you do this so you know where they go) and pull out the entire plug from the back of the fuse panel. Then the plug has a sort of locking tab on each side, you open that up, pop in the wire, close it and plug it back in. The only splicing involved was to the blue/brown right tail lamp wire, I was not provided a wire tap btw, so check if you need to purchase one. The last bit of wiring was just a plug connecting the harness to the pre-wired plug that is taped to the back of the fuse box. You will also need single use plastic expanding rivets for attaching the wheel arch trim, part #51777171004. I got by with removing only 3 on each side, but it would be much easier to just to remove the entire arches or at least 4 rivets. These rivets require a special rivet gun, since they won't fit a standard riveter as I found out. I'm probably going to have to order one of these http://www.sjdiscounttools.com/mar48000.html to properly attach the trim. So in summary you would need to purchase to do the job: 1. Trailer kit - Tischer provides new hex bolts and control module holder, other sources most likely don't. 2. one wire tap if you don't receive one with the kit 3. at least 4 rivets and special rivet gun 4. thread lock for the hex nuts - not specified in instructions but prob a good idea Last edited by jsplayin; 03-04-2012 at 02:59 PM..
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