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.
The Ogre's Fiero Cave