X5 2005 3L D experiences battery warning light and loss of power steering during steering manoeuvres.

[Authorce]

Greetings to everybody. I have a loss of power steering accompanied by a battery warning light when I turn the steering wheel. My brother inspected the engine compartment and saw the serpentine belt come to a standstill, so preventing the alternator from charging temporarily. I think the steering pump or a loose belt. I shall assess the stress today. The confusion arises from the fact that the problem significantly exacerbates and occurs instantaneously when I use the air conditioning. Both seem to own distinct belts, which is rather peculiar! The problem alleviates after the vehicle has been driven for a short duration, occurring mostly while executing a hard left or right turn, and is significantly exacerbated with the air conditioning on. Additionally, after deactivating the air conditioning, I saw an increase in miles per gallon by 4 mpg. Do you have any suggestions?

[RosaStyle]

Remove the belt, and you should identify the faulty pulley by manually rotating it.
Experiencing a grinding sensation or a rumbling sound.
The air conditioning system requires more rotation, hence increasing the load on the belt.

[Authorce]

Thank you, RosaStyle. However, they are distinct belts? Both systems operate from the harmonic balancer pulley, hence I fail to get how the AC load may affect the serpentine belt and power steering. I just can not comprehend it. Does the AC belt need the serpentine belt for operation?

[RosaStyle]

Indeed, you are accurate; I overlooked it (ageing is affecting my memory).
That is rather peculiar, but it must be a pulley, if not the alternator itself.
You should be able to feel the culprit rotating manually.

[Mastervest]

Is the vibration damper damaged?