1992 Toyota Pickup Smoke coming from dash area

Driving home from work, I had smoke, which smelled like burning plastic to me, coming from the dash area of my pickup. I pulled to the side of the on-ramp which I was entering and waited for probably 30 seconds. The smoke stopped and I drove for another 5 minutes to my house. What was the probable cause of this smoke and will I do damage to my truck by driving it further?