Check the electrical wires first, (after you unplug it). If those are fine then check the vent that should go outside, if that is plugged sometimes the lint in there over heats and smells like its burning. Check all your lint catchers and that sort of stuff, I would also pull the dryer out and give it a check allover. Rub your hand allover the outside of it checking for heat. If you have ANY doubt call the local fire department and tell them whats going on. They have thermal gages that they can use too look for heat/fire with. Its better too be safe than sorry!
