I have a 97 T-Top without a factory rear window defroster. It looks like the easiest and cheapest way to retrofit a rear window defroster is to replace the entire rear hatch with one that has the factory defroster glass and replace the heater control assembly with one that has the defroster button. Total parts about $90 from the recycle yard.

Does anybody know off hand if the standard wiring harness includes the defroster wiring or am I going to have to wire that in?

 

Not sure about the harness, but I'd be cautious about finding those factory parts off another car, my 96, and a few buddies 4gens have issues with the rear window tint getting all f'd up, and I'm pretty sure it's caused by the defroster.

 

either way you will have to remove the headliner so when you do you should be able to see if there is a harness there or not.