Santa FE SM (2001-06) :: 2004 - Passenger Side Low Buzz / Whine - Loud When AC Or Heat Defroster On

I have the 3.5 LX AWD 2004 Santa Fe 102,000 miles purchased new. My power steering fluid reservoir was leaking from the top a lot. I read here that the screen in it could be clogged. I went to the garage the manager never heard of such a thing he said, and never heard of a PS reservoir having a screen (I gave him the TS. He said if I got the part and wanted it changed they would change it. I did that. It was done 2 weeks ago and now it all dry under there. But, now.. there is a low whine on the passenger side under the hood toward the back, but when I put the A/C on or the heater on defrost (Not when heater is on, only in defrost) there is a loud rumble/hum from the same area. Shut A/C or defroster it goes back to a low buzz/hum again.

I had the power steering pump replaced at the dealer about 2 years ago, its not old. The noise is NOT any louder when I crank the steering wheel all the way to either side. The fluid since replacing the Power steering fluid reservoir is staying at the same level, full, no leaking. When I put everything on, lights heat only (No defroster), radio, lights the noise doesn't get any louder either, I tested that. The other night after driving about a half hour to and from a place I went to u-turn in a parking lot and that whine was louder for a minute and while driving forward slowly out of the parking lot getting up to speed.

When I asked about the PS fluid reservoir, I had also, asked the repair shop manager his opinion, of that loud hum/rumble when I put the A/C on (At the time I thought it only happened with the A/C when the compress popped on). He listened said "That's the A/C compressor it's going and its going and cost more to replace it then its worth on your 2004." So, that's the background.

Questions: 1. Just wondering if you think it is the A/C compressor that is the loud noise when on, would the A/C compressor even go on when the defroster is on, the A/C is off, and the heat on and there for still make that loud rumble??? Or does that defroster fact kind of mean its not the A/C compressor??

2. What is your opinion of the low buzz/whine noise now (When heat/AC off)? I can't pin point it totally in park when listening, its very low (Except that one point where it was loud for a few minutes driving out of the parking lot.) (The motor sounds a bit louder in it in front too just side observation)

I almost worried if the low buzz was the Transmission as its fluid hasn't been changed in a few years (Because the mechanic said sometimes changing the fluid when its been a lot of miles between can actually cause problems to the transmission) It was done at the dealer around 45,000 miles and now my Santa Fe has 102,000 miles.

Could the power steering pump be going bad in only 2 years from what I've described? Or could the PS fluid reservoir having been spitting PS fluid from the top for a couple of weeks have caused damage to the PS pump now?

The fluid never got lower then full when it was coming out of the top and only when driving, I kept checking it. The mechanic who put the PS fluid reservoir in said he had no idea if it leaked from the top due to the screen as he felt the screen had only minor debris that was not blocking a lot of the screen since its a big screen (He didn't look too hard though), and it was possible even a small crack in the reservoir could cause that same fluid coming out at the top. He said it could be either he didn't notice a crack either.

Or are these two noises possibly not related even though possibly from the same area on the passenger side under hood.