Previously I wrote:
If I remember right, it'* not on the steering column as with older, RWD cars; it'* under the hood, on the transmission, a kind of rotary switch that rotates horizontally when activated by the shifter cable.
Okay, I just eyeballed the thing on my own car, and doublechecked it in the manual. That'* it: The "Park/Neutral Position Switch"
It'* in plain sight under the hood. Look down from above at the left rear of the engine transaxle, directly below the master cylinder, and you'll see the shifter cable attached to the actuator arm, which in turn is connected to a vertical rod coming up out of the transaxle. The switch is the wide black plastic body under the actuator arm, sitting on top of the transaxle; there'* a fat wiring conduit coming in the outboard side of it.
From what I can see of it, the actuator arm shifts the transmission, and the vertical rod rotates the innards of the position switch at the same time.
There is some adjustment to the shifter cable where it emerges from its casing, but I think first you want to find out whether the cable is really out of adjustment, or the switch itself is out of position (if that'* possible). That is, can you select every gear with the shifter in each position, like normal, or is, say, Reverse itself out of position with the shift lever, the same way the lights are?
I'm going purely on what I've seen and read in the manual here; I've never had to do an R&R on this switch, so this is about as far as I can go here. I _would_ say that replacing the switch looks like pretty much of a no-brainer, since it'* held on with only two screws, plus the actuator arm to remove and the wiring harness to unplug, but I wouldn't buy a replacement until I was sure that the existing one was actually toast, and not just out of adjustment someplace, otherwise the new switch will end up just as out-of-position as the old one was.