126 Rear A/C Vent Inop
 

1985 380SE - this is the rear vent behind the center console (under the armrest) that blows at the rear seat passengers. I can't get any air to blow out of mine. I think it would really help circulate A/C through the passenger compartment if it was working.

I've done a search but the info is vague. It appears the vent lever *might* control some sort of A/C flap behind the radio that controls airflow to the vent. How do I trace this cable, and where is the flap that it controls? Can I just wedge the flap open so the rear passengers get A/C?

Also, some posts seem to indicate that the vent only blows heated air. Other posts say fresh (vent) air only. I need A/C air to blow out of there. Is this possible?

TIA!!!

Heated air comes from under the front seats. You should only get cool air or outside air from the center vent.

Are you sure the lever controls a cable? Maybe it controls a flap right behind the vent.

Sixto

Lever controls a cable that runs up to a flap right below the radio. Remove ashray, shifter wood, coin tray and you can see it. Cable typically becomes unclipped at this front flap.

Thanks - I will check it out tomorrow after work. Do you know if the flap provides "vent" air or is it "A/C" air?

If the compressor is on it provides chilled air. If not, it provides outside air. IIRC it will not provide heated air. Mark

The duct that leads to the rear vent draws air downstream of the evaporator but upstream of the heater core.

Sixto

Not knowing the configuration of the hvac box or the relation of the evaporator to the heater core, I'm thoroughly confused.

So can I in fact get chilled A/C air out of that vent if I go in there and fix the disconnected flap?

Air enters the HVAC box from outside the cabin or inside the cabin or a mixture depending on the position of the recirculation flap (open, closed, mix). Air flows through the AC evaporator then to a chamber that feeds the center dash vents and rear center console vent. The remaining air flows through the heater core to another chamber that feeds the rest of the registers.

You can get chilled air to the rear center console vent.

Sixto

Good news. I gently removed the rear slider and vent grill (the whole thing just pops out). The derailleur cable somehow worked its way out of the holding clamp. I separated the cable under the console (it splits in two halves) and yanked out enough slack at the rear, then re-clamped and reconnected the two halves. Buttoned everything up, and now have COLD air conditioning blowing in the back! It seems to be tied in to the front center vents too, so if you close them about half way you get a strong stream of air from the rear of the console!

It's not pysically connected to the front center vents. When you put a restriction across the center vents, the air has to go somewhere :)

Sixto

Just to be pedantic :rolleyes:

If you have the automatic climate control system (like almost all the US cars do) you can only get cold or fresh air out of the rear vent.

If you have the simpler HVAC (knobs and dials system - like many Euro cars do) you can also get warm air out of the rear center vent, not just from under the front seaats.