Hello,

I just bought a 1987 300E, my first Benz. There is a button on the dash which indicates recirculated air. When I push it, the light in the button lights up, but I can't seem to detect any other indication that it is opening or closing a valve. In my BMW 325 of the same year, you could hear an electric motor open a valve, very distinct. Does anyone know where this valve is in the Benz, and should I hear if it is opening or closing?

The A/C (134a) works GREAT...when I'm driving down the freeway, and it works ok at slower speeds, and almost ok at a stoplight. A friend suggested jumping the fan fuse (#7?) Has anyone else done this?

Air control is done pneumatically, so you won't hear an electric motor running. Mercedes loves (at least used to) pneumantics.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

Hi On your veh the in car temp sensor can control your recirculated air flap ,after pushing the switch on it can take up to five minutes if the temp out side is cold ,if a/c is om and its hot the system will go to 100% recirculated air for up to 30 minutes and then go to 80 %,as stated in prior post you will not haer a change ,yet you might feel the cabin cool off faster and maintain cooler air when hot outside.joeym

If you pull the glovebox you can see the far right corner of the fresh air door. You could get someone to watch while you drive and see if it closes. You also can pull the hoses from the switchover valve just under the glovebox and check for leaks. The top two vac lines on the switchover valve control the fresh air flap.

Good luck,

I have noticed that when the temps outside are over 100, my car freezes me like ice. The recirc button is off, but it is still freezing, I have the temp set to 75, I have to direct the vents away from me, so I know that there is a lot to do with the temp outside, as to the temp of the air on the inside. The climate control system monitors interior air temp, ext air temp, if your top is up or down, the new ones even have sensor to detect sunlight and increase airflow in those areas. (2005 SL) I will be excited to see when these things start driving themselves. For as much as they cost, they should. ha ha.

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Brian W. Heitman

www.MBCA.org/northtexas

Join MBCA!!!

yeah...ok brag about it ....

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

I feel this will be a terrible let down for me...

Recirculating air is one of the most important features for me in the car. I prefer the manual control (not by wire) where you pull a lever and a flap obligingly closes the vents and prevents all air from the outside entering the cabin.

My preference for keeping the cabin air tight has nothing to do with hot/cold but with keeping fumes (eg the beaten up diesel driving at the front) and other pollen out of the cabin! Especially driving up the mountain roads in France (the French love diesels).

I realise now that the car decides when the flap is on or off and this really upsets me! I will be investigting on how to hard code it so it stays on or off according to my wishes...