1996 Mercedes Benz 280 airflow

WALTER PICHT

MEMBER
1996 MERCEDES BENZ 280
187,000 MILES

The air flow in my car will only come out the top defroster vent and not switch to the foward vents or the floor vents. The a/c and heat both still work. So I can change the temperature but the air flow stays in the same place

Saturday, June 22nd, 2013 AT 7:26 AM

1 Reply

CARADIODOC

MECHANIC
33,873 POSTS

Sounds like the system uses vacuum motors to change the mode doors and that vacuum hose is broken or disconnected. Most of those systems are spring-loaded to default to the defrost position for safety. Your feet might freeze but the windshield will be clear. Look under the hood for a small plastic vacuum hose going to the firewall. There will also be a small check valve in it. Those valves don't cause much trouble but it could be plugged.