Canadian Mirages get heated outside mirrors, I think standard. I checked out the wiring diagram for the US Mirages and saw that they had the wires for heated mirrors present in the US models. So I went about to do a retrofit.
2 self-stick mirror heat pads, approx. 4"x6", larger can be trimmed to fit as long as you don't cut the grids (I got a pair from Ebay for $15 shipped.)
2 sets of small male/female wire connectors
heat shrink wire connectors or connector of your choosing
10 mm socket and ratchet
plastic trim removal tools
double stick tape or RTV adhesive
1. Remove both mirror assemblies-- Pop the black covers off on the inside of each door. Disconnect the mirror wiring harness. Use the 10mm socket and ratchet to loosen and remove the 3-10mm nuts holding each mirror to the door.
2. Remove both door panels
3. Remove the mirror glass-- tilt the glass up and with a pry tool, pry up on the bottom two claws and the mirror glass pops right off
4. Separate the mirror glass from the backing plate-- heat the mirror assembly in the oven at 200 degrees for 10 minutes to soften the glue holding the glass to the backing plate. Using the pry tools(not knife like I did), pry from the front and behind the backing plate slowly to separate the glass from the backing plate. Once removed, clean off excess glue from the mirror and backing plate. Clean the back of the glass with rubbing alcohol so the self-adhesive heat pad can sick.
5. Line up where the heat pad will be placed on the back glass. You might need to drill holes to allow the electrical male terminals to poke out the back. Peel off the adhesive backing of the heat pad, making sure to get the terminals through the holes, and stick the heat pad on. Start at one end and make sure to get as many air-bubbles out as possible. Using double stick tape (I had circular pieces laying around) or RTV, stick or glue the mirror glass to the backing plate.
6. Before you can run a wire to the heat pad, you'll need to separate the main part of the mirror assembly from the plate that mounts to the door. Underneath, remove the 3 Phillips screws and separate the two pieces apart. You'll immediately see where the wires run.
7. Cut a piece of two-strand wire into about a 2' chunk. Run the wire through the mirror loom from the outside of the mirror into the mirror assembly. Attach two small female connectors to the end of the wire in the assembly and connect them to the heat pad terminals on the mirror backing plate. Reinstall the mirror into the assembly by snapping it back into place.
8. Reassemble the main mirror assembly to the mirror plate and tighten the three Phillips screws. Run 2 strand wire and mirror harness back through the hole on the door and attach with the 3-10mm nuts.
9. Cut the two strand wire with enough length to meet the plug on the door. Once you have enough length, attach a male or female connector to it.
10. On the door plug, cut the 2 wires from the plug that run the mirror heat (gray and black on drivers side, green and black on passenger side) and attach either the male or female connector opposite of what you used in step 9. Connect the mirror harness to the door and the new mirror heat harness and zip tie into place.
11. Put the door panel back on and snap the black mirror cover back into place.
12. Now your mirror will heat when you push the button for rear defrost.
Sorry the directions are a little more vague then I wanted, I did his back in April. Just got around to the DIY post tonight. Hope this helps.