My grandpa is having a problem with his 1999 Cadillac Deville. Whenever he has the A/C going, there is a clicking coming from the dash. No air comes out of the front vents, however it will come out of all the other vents (floor and defrost) and still blows out cold from the ones that work. He took it to the local stealership and they said it would cost $600 or something dollars to fix.They said it was some motor inside the dash that they would need to tear out the entire dash to get to. Does that sound legitimate? I never really work on Caddy's or A/C systems in general, so it's all Greek to me.