Because Matixowners is shut down, here is a snapshot from the internet archive.
Since I have a manual, here's the part I was interested in:
For the 5-speed Matrix owner, read on.
10. Clutch switch. Apparently all 5-speed Matrixes not made in America do not have the clutch switch installed. Since Matrixes are supposedly all made in Canada (like mine) they all need the switch.
Get on your back under the dash, look up top where the clutch pedal lever ends and remove the bolt and nut that act as a clutch pedal return stop. You may have to remove the dashboard change drawer (lower left of the steering wheel) to gain access with a socket and extension to this bolt.
Now install the clutch switch where you removed the bolt. After adjusting the switch for proper engagement, tighten the lock-nut. There is a wire assembly under your dash that has to plug into the new clutch switch. Mine was dangling free next to the clutch pedal lever against the firewall. Plug in that wire assembly to the new clutch switch. (If you think you already have a clutch switch, you may be looking at a starter interlock switch. New pics are shown later in this thread showing the difference in the switches.)
Clutch switch wires and plug as found under dash.
Hook your battery back up. Clean your car up and go for a test drive!!
When all is well, set your radio back up, and if you got that annoying seat belt beep back again go here for that procedure.
http://matrixowners....showtopic=45649
This job took me about 3 honest hours due to getting all my tools out, figuring out how to make the steering wheel cover hole, figuring out where the clutch switch went, taking pics, cleaning everything up, and resetting my non-factory head unit.