w123 fresh air vent closed or blocked

[TotallyImpractical]

My Benz does not air-con so my question is about the fresh air vents on the dash and how to get them working properly.

The center switch beneath the air vents does nothing although, I assume, it should open or close them. It just slides back and forth with no effect.

The vents only allow fresh air into the cabin if the blower is turned on. Is this normal and if not, how can I get them to let in a constant stream of fresh air without turning on the blower?

Thanks!

 

[mikestrivens]

On my W124 the blower has to be on. When the blower is off the vents are all closed to stop external air coming into the car. If you turn the fan to off you should be able to hear the flaps closing to block the vents. The lowest fan speed should be virtually inaudible but in this position the vents should open and work normally. The centre vent should then let in external fresh air, which you can control with the little thumb wheel under or between the centre vents.

 

[television]

The flaps are all vacuum on a 123 and worth checking the pipes

http://www.detali.ru/cat/oem_mb2.as...+++717.401&CT=F&cat=222&SID=80&SGR=120&SGN=04

http://www.detali.ru/cat/oem_mb2.as...+++717.401&CT=F&cat=222&SID=80&SGR=105&SGN=03

 

[stever]

The flaps are all vacuum on a 123 and worth checking the pipes

http://www.detali.ru/cat/oem_mb2.as...+++717.401&CT=F&cat=222&SID=80&SGR=120&SGN=04

http://www.detali.ru/cat/oem_mb2.as...+++717.401&CT=F&cat=222&SID=80&SGR=105&SGN=03

Sorry that's wrong - vacuum is only used on W123 ventilation if it has air con.

Fresh air should come through the centre vents when on the move regardless of fan speed, unless you've got the slider to the closed position. If the slider's not doing anything then then it probably has become detached from the flap mechanism

 

[TotallyImpractical]

That's what I thought....that I should at least be getting fresh air if the slider is open even without the fan being on.

I'm fairly handy....can I fix this myself?

 

[stever]

I don't know as I've never had this problem. Hopefully it doesn't mean taking the dash out!

 

[television]

This is the air guide

http://www.detali.ru/cat/oem_mb2.as...+++717.401&CT=F&cat=318&SID=83&SGR=165&SGN=06

and the heater box

http://www.detali.ru/cat/oem_mb2.as...+++717.401&CT=F&cat=318&SID=83&SGR=030&SGN=01