So I found a lot of questions, a few answers, and zero clear pictures regarding the notorious reverse light switch, which has a tendency to fail on MkIVs, leaving us with no back-up lights. Finally after digging around in my car three times, and four trips to the dealer, I got the right part and got my backups working again. (Woo!) Behold, the DIY:
(nondisclaimer goes here)
0. First, you gotta get the part itself: 02K 945 415 C. The diagram in the parts selector is confusing cause (a) there's no sealing washer and (b) the diagram of the transmission is almost completely wrong. But that's the part you need.
[[Had to remove the picture]]
Tools required: nicely enough, all I needed for the whole affair was (I think) a 10mm bit and a 12mm bit, plus pliers for the air filter tubes and a wrench for the switch itself.
1. Open hood, let engine cool down, remove battery cover.
2. Remove battery terminals and the cable to the fusebox (or whatever it's called). Then remove the stuff around the battery, including 10mm bolts that hold the battery "box" in place. Also give yourself some room by removing the back covers to the driver side headlight. Finally, remove the restraining piece that holds the battery in place (12mm bolt) and get the battery out of there.
3. The back of the battery box is a separate piece that clips to the front part. It's held in by two 10mm bolts. Plus the cables to the fuse box run down the back and are held in place by a clippy piece that folds over. It's surprisingly hard to unclip!
4. Just keep the fuse box dangling there. Now you've got a clear shot to the battery base, a big plastic piece held in by four 10mm bolts (one already removed here).
5. Alright, almost time for business! The upside-down golf club piece is your shift linkage, and it's bolted to the top of the transmission.
6. Zoom in a little closer... see under all those cables?
7. <flash on> Bing! There she is:
8. Disconnect the switch plug. There's a tab on the end you gotta pull.
9. Now you're ready to unscrew the switch. Except! You don't have enough room to turn the wrench. So you gotta pull the air filter box too. Here it is:
It's held in by two bolts and rubber gaskets, which oddly just popped out for me. On the driver's side the filter connects to the air intake and has a little support that holds it in place. On the passenger side it connects to two air outtake tubes (big and little) and the airflow sensor. A better look:
Pull off the tubes and pull the airbox out of the car. Ahh, now there's some room to wiggle.
10. Even now, it's a tight squeeze to get at the reverse switch and unscrew it. This would be a perfect time for a self-ratcheting wrench, but the reverse light switch is like 1 millimeter bigger than my largest one. So instead, I grabbed an open-ended wrench and managed to turn it 1/6 turn at a time:
11. Done! Old, meet new:
Installation is the reverse of removal, as the manual says.
Voila! I would have taken a picture of my reverse lights working, but I was alone and - think about it - that's kinda hard to do.
Let me know if I got something wrong. Hope this clears it up for some people!
Modified by happywaffle at 2:10 PM 3-16-2007