Loud noise/vibration when using heater or air conditioner on 1998 Oldsmobile Intrigue

When I use either the air conditioner or heater I get a very loud vibration/noise. It still heats or cools, but so loud it can be heard outside of the car. What is this? I tend not to use it except for a minute or two at a time, then turn it off. This happens EVERYtime I use either and starts within 15 seconds of turning them on.

by in Martinsburg, WV on December 06, 2012
3 answers 2 comments
ANSWER by , December 06, 2012
Blower motor bearing worn, debris in blower wheel. Remove fan unit clean or replace.
COMMENT by , December 06, 2012
Thank you...i'll start there.
ANSWER by , December 06, 2012
blower motor bushings or fan blades are bad
COMMENT by , December 06, 2012
Thanks for taking the time to answer, i'll check it out.
ANSWER by , March 28, 2013
ac compressor