Hello - I own a 93 Corolla that is in good shape, only 160k on it. No major maintenance issues. The car, however, has no rear defroster. This was not a problem until I moved to Chicago recently. I have rigged up a small blower powered by the cig. lighter to the back window, but it is too small to be very effective. Does anyone have other creative solutions for this? Devices? Windshield de-icer INSIDE the car is starting to make my head spin. 
Thanks!
I tried the aftermarket rear window grids, but these were never satisfactory. The car involved is a 1978 Cutlass Salon–a fastback. It didn’t come with a rear window defroster. I mounted two small fans on either side of the rear window on the package shelf and connected them to a switch I mounted under the dashboard. This works well and the rear window clears in the 2 miles I drive to work. It must look a little goofy because my friends make fun of my arrangement. However, I remember when we used fans often mounted on the steering column to defrost the front windshield back the the 1940’s. You can probably pick up two fans for under $15.
If it’s icing up inside the car, the issue is probably that you have too much moisture in the interior. Going on a long drive with the heater on or parking it in a heated garage with the windows down or putting a space heater in the car overnight will help clear it out and investing in a set of rubberized floor mats will help keep the moisture at bay.
Another possibility is that your car is likely wired for the rear defroster and you may just need to get a switch from the junkyard or the dealership and then any glass shop should be able to get you a rear window with the defroster grids.
Thanks, both for the advice. It had not occurred to me that I might already be wired for it. Makes sense, though.
Please keep in mind that cars with rear window defrosters have heavy duty alternators as standard equipment. You might check to see what the current draw would be. If the car originally could be equipped with a RWD, check a wrecking yard for a rear window with the wires already in it! Unlike windshields, there is little demand for these, and the price should be reasonable!
I recall most 93 Japanese cars already had them or their upscale model had them with other options.
Good luck!