98' S70 GLT 150k

#1 lately I have been hearing a noise, would describe it as a sound similar to a break grind/electric motor whine) the sound is originating to the best of my analysis directly behind and below the battery. the sound will come on usually when the car is started up wont last for more than a few minutes, and then you can hear the sound slow and drop(making me feel it is something like a motor or compressor type sound(almost reminds me of my old 70's starter solenoid whine... then sound comes on very rarely when I am driving, if it does it usually can be even shorter in duration.

not sure if they are related but-----

#2 Since it is now getting warmer up here in the NE, I also tried my A/C yesterday, had it recharged maybe 2-3 years tops, and worked fine at the end of the season last year.

I am not seeing any codes(other than the code I have fore the altitude sensor which wont go away[and I am not planning any mountain trips])

I am asking for any input from the great brickboard minds,

Many Thanks

FRed