W114, only passenger side defrosts windshield.
 

So I discovered today while driving in the rain that only the passenger side windshield vents are open. Drivers side stays fogged up while the passenger side is crystal clear. Has anyone been inside that area of the car to know what causes that? I assume the sliders control the flaps via some cable, maybe one snapped or came loose. If the slider controls are a pain I'd at least like to get the windshield flaps in permanently open rather than closed. Please let me know!

I'm betting the hose that goes to the L side windshield vent is disconnected or missing. It typically happens on the driver's side because that's where people are typically in the dash doing something like instrument cluster or ignition work. There is no control to separate the L from the R side windshield vents.

Best Regards,

David

W114 chassis have left and right hand heater cores and controls for heat.

If the left side isn't defrosting, it may also be because of a no heat condition on the left side.

Heat is regulated by a valve on the firewall, controlled by a bowdin cable.

Jim

I'm getting heat on the drivers side dash vent. I should add there is no air flow to the drivers side windshield, whereas the passenger side is getting air.

Then it's an airflow problem.

The defrost uses a single fan, located in the most remote location possible in front of the heater core. If you are getting airflow to the pax side, then as suggested, it must be a disconnect or blockage to the defrost outlet.

Jim