On my 2010 Mercury Grand Marques on a/c the air rotates from vent to defrost to floor. Does anyone know what went bad?
Sounds like the inline vacuum check valve. If this happens when you accelerate, it's definitely the check valve. HTH. -Jim
I need to have it checked out, thanks for the help
You're welcome. Glad to help. -Jim
Looking for a Used Grand Marquis in your area?
CarGurus has 2,557 nationwide Grand Marquis listings starting at $1,300.
Search Mercury Grand Marquis Questions
Mercury Grand Marquis Experts