The sensor for the key sits on top of the key barrel housing. When I looked at mine, I found that the solder joint between wires and the contacts was completely separated. This was both on my car and a spare housing I got a while ago (needed new ign switch).
To get to it:
-Remove trim under steering wheel
-Remove key barrel (key in and to acc position, press small metal button in and pull out of housing)
-Unplug 2 things, main one is ignition switch and the other is for the sensor (not reconnecting this is a possible reason for your problem)
-Remove the housing (loosen band securing it, push in another metal button and pull out)
On the housing, you will see an off-white plastic box with 2 wires coming out and a small button facing the key barrel. Use a small screwdriver to remove the top part, the wires and contacts will come with it (be careful not to lose the plastic button that goes into the housing when you do this).
If the solder is like mine, the wires will be totally separated from their contacts. Press the contacts out of the plastic and resolder them to the wires. Reassemble everything (again don't forget the plastic button).
Note that there are 2 more wires for another part of the sensor, which detects when the key is pushed in (for acc -> off), I didn't have any problems with it though.
I'm assuming of course that the auto feature wasn't just turned off (push switch beside height adjust) or a fuse blown. If it is none of these it's possible that they cut a wire installing the immobiliser.
