Quick question. I decided to flip the rear defrost button on just to see if it actually worked. When I tried to switch it off it stayed on. Is my switch no good? Am I missing something? It has on and off on the button.

It's been a while since I've had one with a defroster, but I believe it will time out if you don't press it again.

Then why does it have and off function on the button. I depress it down and nothing happens???

I don't know. Like I said, it's been a while. Could be your switch is bad. If you turn off the ignition then back on, does the defogger turn off? There's a defogger timer relay in the system, it could be sticking.

Switch running timer.
Timer is near brake and gas pedals.
One of them is bad/dirty.

Lighted Dash Switches doesn't come apart to clean easy like Fiero PW because of bulbs.
Timer is in a metal can.

Defog "relay" should shut off after 10 or 5 minutes first time, 5 or 2.5 minutes after, each time the engine runs. If does then timer is likely good.

GM used short Timer values for Fiero and never bothered to update SM. (Other car lines have 10/5 minutes) 22p is 10026005 and is 5/2.5 minutes.
Timer numbers are on the case.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

ok but this doesn't answer my question, does the timer effect whether the off function on the button works?

Pretty sure you should be able to manually shut it off.

Agreed, you should be able to manually switch off the defroster by pressing the button.

that my exact point, I am pressing the off button but the light stays on and the heat is still coming from the window. I had to shut the car off to reset it.