Bad alternator?

[Tim/M45]

Just checking to see if anyone with more knowledge than I can steer me in the right direction. Recently, the warning lights for the battery and brakes on my 2003 M45 have been coming on together. They would go out after a minute or two. Well now they come on and stay on, along with the charging system warning on the center display. I can get them to go off if I hold the engine at a high idle but my multi-meter tells me the battery is not charging. Seems like a straight forward diagnosis of a bad alternator but the brake warning light being on with the battery warning light is throwing me off. The battery is less than 2 years old.
Thanks.

[Gene Ln]

this is generally the case, when the charging system is faulty all the dash lights can/do come on. I suspect replacing your alt will stop the problem entirely.

[EdBwoy]

Ditto on the charging system.
Before focusing on the alternator, how many miles does your car have and what is the health of the main accessory drive system - belt, main tensioner and pulleys?

[Tim/M45]

Thanks guys. The car has 146k miles. The belt is about 3 years old and looks good. Tensioner and pulleys seem OK but I'm not sure how to verify proper tension. I watched it closely while running, and at a high idle. It does not appear to be slipping. AC blows cold at idle so I believe the belt is tight enough, (I hope)