Started car and pushed a/c button and nothing came on. I hear the normal click sound you hear right before a/c turns on but nothing after that. A/C had been working fine before this. There's absolutely no airflow with all push buttons, no fan motor noise, no air flow in all vents. I purchased the car 4 months ago with 168k miles on it. Car has been perfect until this happened. 1989 420SEL...Please help. Thank you!