My '86's defroster only stays on for 2 mins. I got another used defroster switch/timer, and that only stays on for 2 mins. Can they both be worn out? My grid seems Ok. Does Chevy still sell them, if so how much? Or is it something else?

 

I believe that they are purposely timed so that you don't leave it on indefinitely. I don't think there's any harm in turning in on again after it has shut off a couple of times, but imagine if you left it on for a couple of hours of driving, you might burn up the grid. Notice that the switch is not a two-position switch, it's click-on/click-off/center (high-impedance?). Hope this helps.

 

They're usually timed for 10 minutes or so. Sounds like yours may be overloading, maybe due to a poor connection at the ground wire on the passenger side. Check all the connections on the struts to be sure they are clean and tight.

Pete