Burning Smell and High Pitched "Humming" Noise - H

[Chet]

Long-time reader, first-time poster.

I have a 2002 Pathfinder LE. Getting ready to take a road trip next month out of the state and am all of a sudden having problems with my Pathfinder. 3 days ago, we started the car and made it approximately 1 block and noticed a burning smell inside the vehicle. The heater was off as were the heated seats. I pulled over and opened the hood and the smell was much stronger - seems to be coming from the passenger side firewall area. The same time this started, we heard what sounded like a soft, but high pitched "humming" coming from what seems to be the same side of the motor.

Any ideas on what this could be. I'm being told that my power steering may have an issue. I should note that this burning smell comes and goes and the hum gets higher pitched as you rev the engine (in gear or not). Like I said, we are getting ready to take a 1600 mile road trip next month and are worried that there may be an issue that needs addressed first. Any suggestions would be appreciated.

Thanks for reading!