Mk4 generation VW use a slightly different ignition switch. Mk5-mk6 are about the same and all VW are close enough to that they're all included in this article.
First you have to remove the trim below the steering wheel and the lower steering column trim.
For mk4 VW Jetta, Golf and Passat, see 1000q: trim removal (Passat shown but other models similar). Steering wheel removal is not required.
For mk5 (and probably newer) you have to remove the steering wheel. See
mk5 steering wheel removal. The full article is for
forum members only but enough is shown that you can get the steering wheel off
if you don't feel like signing up. Then you have
access to remove the lower steering column trim (2 torx bolts below).
If you're replacing the ignition switch, make sure that nothing is melted or that the wire harness is intact because the ignition lock cylinder and switch are fairly reliable.
12mm triple square bit (not torx!)
small phillips screwdriver
First watch this video, it explains some of the things mentioned in the
procedure. A mk5 is shown but it's pretty much the same for earlier and
later cars. The entire assembly is removed from the car for illustration.
If you have a mk4, remove the purple plug at the end of the lock cylinder
assembly. Then remove the 2 screws covered by red paint. You can now
slide the ignition switch out. If you need to remove the lock cylinder, remove
the turn signal and wiper stalk. See 1000q:
turn signal removal for details. As you can see, there's a lot of dust
in there so it tends to get dirt on the contacts and click. Now would be a
good time to clean it as much as practical.
If you have a mk5, the ignition switch is at the end of the assembly shown
below. To remove the lock cylinder you may have to remove the clockspring
and turn signals. It should be obvious how to remove them now that the
trim is off. There are a few tiny torx screws and plastic hooks. If you can't figure it out, feel free to sign up to the VW
TDI forum and Audi TDI forums.
Here is more detail on the assembly. To remove the steering column lock assembly you have to drill out
the 2 snap bolts holding it to the steering column. In my case I just cut
it off since this was a spare steering column.
To remove the lock cylinder-immobilizer antenna for all mk4 and newer, turn
the key to ON and insert a paper clip through the hole shown. See the
video above for a demonstration. Don't worry, this info can't be used to
help steal your car. The key must be turned to ON for the paper clip to be
able to release the unlock. If you use a screwdriver to try to turn the
cylinder it will just spin the assembly.
Here is more detail on the latch if you didn't catch it in the video.