My 92 doesn't have one. The rear window however does have some type of grid (horizontal lines which cover the top 1/4 or so of the window). Is this a defroster grid that jusst lacks wiring? thanks

 

No thats just a sun blocker, they do make custom kits to do rear defroster, and you have to wire it up your self and paste on the wires to the window. The best thing to do is just go to a junk yard and get a used rear window that already has the stock wires on it and just wire up a transformer and power to it. My Camaro is the same way, I don't have the center consal option, where the trunk release and defroster options are but I wasn't lucky when I got my Camaro so I live with it.

 

The defroster switch is below the cigarette lighter, not on the console.