73 450sl heater controls
 

The defrost mode works great, blows hot air at the windshield but the heater mode does not blow air into the car area. Has anyone else had this problem?

its broke............default mode is defrost....

JBR:

I haven't had the problem with my '72, but my indy mechanic tells me that the vent shafts on older SLs with levers to shift the heat/defrost air control would sometimes sieze up and the levers would not move properly. When this happens a mechanic would sometimes loosen the levers on the shafts so they move freely. Leaves you with the impression everything is working, but the flaps do not actually function so the air does not shift from heat to defrost. Maybe this is your problem. It will not be easy to fix, lots of dash/console disassembly to get access. The CD ROm manual is not much help with this either, the information focuses on removal of the entire heater box assembly, rather than specific info on repairing and adjusting the control levers. What you get for adjustment info assumes you have the whole unit out on the bench.

Good luck,

230/8

The problem usually comes from air in the cooling / heater system on your car...Please check it out...
If u don't found something wrong in there...please take your car to dealership and check everything related with air control...