Extremely light high pitch sqeel at 1/4 throttle on a 01 325

Extremely light high pitch sqeel at 1/4 throttle on a 01 325i.?
I have the very annoying faint high pitch sound that looks to be on the drivers side. I don’t have idea what it's and iam inquisitive if anybody eles experienced something like this. Its not a brake sound, nearly sounds like its coming from the AC vent. Blower motor works great and looks to be on driver side only.

This isn't a belt squeal this is a high pitch light sound. Its hard to explain. This is gonna sound crazy but its like when you go and get your ears tested and they shoot that high frequency sound into your ear that is what this sounds like.

Check the air boot from the air box to throttle. particularly where the boot connects to idle valve. it's hard to see, but you may be able to reach your hand in the tight regions and feel for tears. good luck.

There is a electronic box fan that will make that sound fits all concerns except for the 1/4 throttle . it's down by the pedals. if you remove the lower dash panel by the pedals it's in the upper left corner.

I think it may be some belt. alternator or timing belt. have it checked out.

Try turning off the A/C. If there's a problem with the AC or the AC belts, the belts should stop squeeling when there's no load. If you attempt turning the steering wheel with the A/C off, and you hear a squeel, they the Power Steering belts can be too loose. If you have a faulty water pump, you'll hear a metallic squeel and a stuck or broken pump. Look around under the hood, and attempt to find out which area has the problem. Then FIX it before you have a serious problem.

I had a 325ci and it made a high pitch squeel that comed from what they believed was an air leak in one of the valves but said it was no threat to the motor so it did not need fix.

This sound may be from the air con compressor bearing or clutch,alternator bearing,power steering pump bearings,the water pump,the clutch for engine fan may be vlave leakages.
Please trace one by one.otherwise drive to dealers or qualified mechanics and they shud give you the results free of charge.
Repairing it, is your choice, place.and time.

wish you the best