I have an 01 LS and the problem just started today. After you let the a/c run for a few minutes and then turn it off the car starts smelling like burnt plastic on the inside. It's not coming from the main vents and it's not coming from the engine compartment. I just can't pinpoint it. Any suggestions would be appreciated.

 

is it coming from under the dash

 

The smell is strongest when you're sitting up. I was trying to check under the dash on the passenger side and it wasn't that strong.

 

I've noticed a funky smell occasionally in mine as well. I'm not sure try takin out the vents and checkin in there

 

Could possibly be the blower control resistor. The thing is, the resistor is sitting inside the blower chamber which is located under the dash (passenger's) side. So if the resistor is having a short of course it ceates a spark and hence the smell.