I just ordered my kit for the BMW E46 Electric Rear Sun Blind (BMW part# 51460004718) and look forward to installing it over the holiday weekend.
Because the original BMW .pdf file for DIY Installing a rear electric power sunshade aka electric sun blind or auto / automatic rear sun shade is very confusing and put together completely wrong most likely from a botched attempt at translating the original german, I reorganized the text and images in this more coherent JPEG version for all to print out and use.
CLIFF NOTES for steps (a.k.a how easy this is):
1. Remove glove box, ashtray cubby console w/ console switch bar, rear seat back and rear deck.
2. Cut out a hole that is pre-shape/pre-lined up already on the underside of the rear deck for the sunshade.
3. Insert sun blind. Run wiring from deck to right side foot panel/door sill (a lot easier than it sounds because all our LHD cars already have a main branch of wiring running down that side)
4. Reinstall rear deck. Reinstall seat back rest and seat cushion if you removed it.
5. Run wire under door sill (and B P!llar) to glove box area. You don't even have to remove the sills or the p!llar because you can easily tuck the wires under the sill where is overlaps the carpet.
6. Once at the glove box area tap wire into fuse box and the supplied button control switch.
If you are using a uni-button switch or if your kit comes with a uni-button switch (most likely since all retrofit kits come with the uni-button) then you will eventually prefer getting the newer unified all in one console button bar. Buy the bar and then tap the yellow and white wires from the original kit's 2 pin button harness into pin 14 and 15 on the large connector that plugs into the console button bar.
I'm saying this because the uni-button is for pre 2001 BMW E46s and will NOT fit into your 2001 and later E46 button bar style console switch. After you are done put everything back togther and viola.
The only key areas of difficuly will be properly cutting out the hole in the rear deck. BMW already has it pre-outlined on the underside showing you where to cut. But getting the proper saw to get a clean precise cut is tricky.
A traditional hack saw or dremel rotary saw is not going to cut it (excuse the pun). Pneumatic Power Saws are a tad bit strong IMO since you would have to secure the deck so that the Saw won't shred everything the minute the blades hits the plastic.
I am using a basic household 12v Black&Decker Drill with a special drill bit I got from Home Depot that is made to actually cut thru plastic as if your drill is a saw. This way I can drill my starting point along the pre-outline on the underside of the deck and just run the bit down and around the outline of where the hole for the shade needs to be.
Another key issue is the confusion of the sun blind control switches. Most DIYers with post 2001 e46 cars only realize after the fact that they have to purchase an entirely new version $200+ button bar with all the buttons (heated seats/dcs/hk/sport/tire/sunblind) on it just for the sun blind button and this can make this project annoying and unexpectedly more expensive than you may think at the start of it. You can use the big uni-button the kit comes with but there is literally no place for it to fit on your console dash if your car is a post 2001 E46 (you can however still wire it up to the sun blind and keep the large button tucked away in the glove box or inside the sunshade cubby)
Enough said...now here I present the "corrected" JPEG version of the original BMW PDF file. This should make this ultra rare and coveted Retrofit DIY more pleasant to comprehendable to the average BMW E46 driver.
Also my pictorial DIY of the process will be up by the Fall.
E46 SEDAN Electric Rear Sun Blind: