Installing/fixing rear defogger?

I bought my car ('00 Corolla) used, and thought it had a rear defogger, but it…doesn’t. It has the heating elements across the rear window, but in the spot on the dash where the button to turn on the defogger should be, there’s just an empty void. No button. What would be involved in fixing it so I can defog? Most of what I read is about repairing tears in the heating elements or finding problems in the wiring, not about putting in the wiring.

Also, I live in an area without snow, so this is just for when the windows get fogged up. I’ve had big problems with that lately…I wipe condensation off the rear window (outside) before driving, but then when I start driving it fogs up again. Is there a product I can apply that will solve this problem instead?

You can try a rainx Defogger product, but I would try 2 things in addition, make sure your system is not set on recirculate, and crack the back windows open a tad to bring in dryer colder air. If the wiring is there where the switch is missing, a new switch should be easy, but It was probably removed for a reason, such as blowing a fuse. Proper testing could find the fault in the system if that was so.

Also, make sure you have a/c buton on, and heat set to max.

I have no idea if these are good, but here’s a kit for cars that don’t have a factory defroster:

I used the Frost Fighter Tab repair kit with good results. Unlike the Permatex repair kit it worked.

Ed B.