did a search but did not come up wiht any real answers

i am putting this into my 91 formula, it already had the wires going up to twhere the stock switch goes in teh dash, and runningh back to the back of the car to the struts. I go ta window and all i have left to do is put it on, my questin is am i going to need to add a relay anywere or can i just plug it in and be al set or is there something else like a realy or something i will need to add, like i had to get for my foglights ?

 

Here is the schematic for a '89 camaro, it should be basically the same on your car. There is not a seperate relay on ours for it.

 

so assuming i already have the wires for the defroster in the back and i got a switch, and i have a deforster hatch, it should just be plug and chug right ?

 

There is a seperate relay on the Firebirds that mounts behind the bolster trim at the bottom of the dash on the passenger side - not the hush panel, it's the long narrow one just above it. It's usually a silver metal case, about 1 by 1.5 by 3 inches. There may or may not already be a plug-in for it.
If you can find one in a parts car, part of the wiring should plug into a junction panel behind the drivers kick panel.