i have 89 camaro iroc-z28 i scrap off the window tint and also scrap off the defroster grid,is it hard to repl

either you do not worry about a rear window defroster any more or you get a new rear window. Shop around before you by you can find good deals on them new or used.

it is impossible to replace the defroster grid the only way to that is to replace the rear window completely and if you scraped the tint off you spent more time than you needed to now you have a couple hundred dollars worth of work to get done

Yeah, that stuff is conductive paint that heats up when a current is passed through it. They do make a touch up to connect the lines in case it gets nicked or something. If you removed a lot and want your defrost then you'll probably need to replace the window.

Window tint is usually peeled off, not scraped. If you damaged the grid, you will be much better off to replace the window.

impossible to replace it with out getting a new rear window