I hear a weird noise and a squeaking sound coming from either the tensioner pulley or the alternator. The sound is present the whole time I am driving it. In addition, about three months ago, when I turned on the AC/vent switch, smoke and a burning smell would start issuing from under the hood.
The noise and smoke is most likely coming from the AC compressor and pulley. The compressor assembly, drier filter, and possibly the condenser would need to be replaced. Also the belts should be replaced. I would recommend having a mechanic, like the certified ones at YourMechanic, come and check it out for you to see what is causing the problem.