Heater smells after 5 minutes

What is your question?

When I turn on my car heater, it works as expected but after around 5-10 minutes it begins to smell like burned plastic and I have to turn it off. This happens when the heat is set to 80's-High heat. No issues with A/C.

What makes this problem better or worse?

After the heater has been on for 5-10minutes

How long has your 2008 Dodge Grand Caravan had this problem?

Months