Squeaking Noise At Front Of Engine

My 05 TB has a squeaking noise some where at the front of the engine. I have replaced the belt tensioner, still have the noise. could anybody give me advice on what to check and how to do it. the truck only has 58, 000 miles. i washed the engine over the weekend and thats when the noise appeared you guys have always been right in the past. thanks in advance for your help.

Tough to diagnose noises from here, remove the belt and run the engine see if the noise is gone. If so feel each pulley for any anamolies.

Thanks maxwedge, it was pulley between alt. and a/c comp. Replaced and so far so good!