Ford Repair: Burning smell, ford explorer, engine compartment

Question
I own a 2002 Ford explorer XLT, recently, my wife detected a burning plastic smell from the engine compartment, and not sure if it's the air conditioning unit or the engine, any thoughts or ideas would be appreciated, thanks in advance.

Answer
The most common reason for a burning plastic smell is a plastic shopping/garbage bag melting on the exhaust system.  The smell comes in the passenger compartment through the air inlet on the cowl panel below the windshield.

I hope this helps,
Dave