BMW X5 E70 Rear Hatch Won't Lock

I have a 2012 BMW X5 (E70) and the rear hatch wasn't latching. I loaded the rear, lowered the hatch and started driving. I noticed that the light was on inside as I was driving. When I got home, I found that the hatch wouldn't close or latch. It would open (from the inside button, rear button, or fob), but when it closed, it would get close and the release. Slamming it didn't help.

I looked at some of the posts on BimmerFest and elsewhere, and tried a few things. I pulled fuse 121 from the rear (behind rear tail light), but it didn't work.

At this time, I started looking closer and noticed that one of the bolts holding the u-bolt in the lower rear hatch was loose. The bolt was there, but as I grabbed the u-bolt, it moved. I'm pointing to it in the image below. The u-bolt would be where the second knuckle of my index finger is, and I'm pointing at 1 of the 2 bolts that are here.

I could wiggle the u-bolt at least 1/4" and maybe 1/2". I suspect that the upper hatch tried to grab the bolt and attach, but couldn't, so it opened again.

I looked at a parts diagram to see how this worked. I could see there appear to be only two bolts, despite the fact that there are actually 4 openings, and there mechanism under the ubolt has a few pieces

I tried to screw the bolts down. One grabbed and tightened. One would not catch, so I had to take things apart. I started by loosening all the screws on the lower hatch. These are on top when this is open. They are behind the flap that folds down on top of the lower hatch. You can see these below. These need a Phillips screwdriver.

Just a note, you need to hold the flap up (it's just visible at the top of the image below.

Once this is loose, you need to prey it loose from the lower hatch. The side closest to the hinge will pop out with a little prying around that edge.

The side furthest from the hinge actually wraps above and around to the back of the hatch. There is a plastic part that is on the outside. In the image below, I'm pointing at part of the seam. This has tabs near the lower (if closed) edge of the two plastic parts. I managed to carefully pry these and pop them loose from the inside.

Once you have this piece off (it's about 4ft long, about a foot wide), then you will see some of the wiring, and another plastic piece that covers the u-bolt. The u-bolt has a plastic cup that covers it, and from this side (when the hatch is open), it sticks out.

There are 5 Torx bolts holding this down. I am not sure of the size, but they were one of the larger Torx screwdrivers I have. They've likely been in this car for 8 years, and never moved, so they were stiff and hard to remove. Once out, I could lift this panel and see the mechanism below.

What I found is that there is a metal assembly that holds the locking mechanism, and a black spacer that centers this. The u-bolt attaches to this. If I get the spacer to fit correctly inside the mechanism, I can press the entire assembly up to the hatch and my bolt will then reach the threads inside. I had to fuss with this for a few minutes to get it aligned and then have the spacer slip inside the assembly before I could get this correctly put together.  There are wires to the assembly, so I was working bent over with the ensure section only slightly lifted off the lower tailgate.

Once I did this, I hand tightened the bolts to hold things, and then found a wrench to snug them up tightly. I have no idea of the torque, but I made them fairly tight with a small adjustable wrench.

I assembled back the inner plate with the Torx screws, ensuring the wiring was placed below. Then I snapped the outer plastic back on and tightened 2 screws. I tested the hatch and it worked perfectly. I finished adding in the other 3 screws and tested again. Working hatch.

This took me about 20 minutes of fussing with panels and looking at the diagram and parts. It's not hard, but if you have latching issues, double check the bolts are tight and the u-bolt doesn't move.