W124 - Heater Window Demist Not Working

simonr66

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Your Mercedes
1992 W124 300TE
I have recently purchased a W124 300TE 1992 with Air Conditioning (not climate control), so have just joined the forum - hello everyone!

The fan blows hot / cold air to side vents and floor vents but no matter where I position the heater regulator dial no air comes out the window demister vents.

I have been searching the forum and am aware of the vacuum pod system - which are supposed to behind the glovebox but I have taken mine apart and can't see any Y7 valve or pods - but can see the regulator wire moving a lever on the bottom of the heater box - was the vacuum system on all W124's or just the post facelift models?

Mine is a RHD car - unless the Y7 valve is on the other side!!! Would be good to know before I start ripping that apart...............

Does anyone have any further experience of what my problem could be?

Thanks for your anticipated help!
 
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hotrodder

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Your Mercedes
'93 320te, '54 ragtop beetle (in bits)
It's only automatic climate (one temp dial and push buttons for air direction, fan speed etc) that's controlled via vacuum. When the air direction is done with a rotary knob cables and rods are used to move the air direction flaps

Cross your fingers, keep an eye out for black cats and take the centre console apart... if you're lucky the problem is at the heater panel end i.e. one of the cables at the air direction knob has come adrift or needs adjusting. There's two cables, one for the footwell and one for demisting. If a cable has broken or the cable, a rod, one of their retaining clips has come adrift at the heater box end and/or the air direction flap itself is jammed most of the dash may have to be taken apart to get at things

I know this is for a 107 not a w124 but is the closest pic i can find from a quick look around the internet

487874d1357297537-reduced-heating-dash-vents-winter-ventilation-controls.jpg


If you're not already aware of how to get the heater control panel http://www.w124performance.com/service/Index/Groups/68InteriorTrim.htm 68-200 will guide you through removal of the centre console trim. Unfortunately the HVAC section of that (and all the other online workshop manuals i'm aware of) only really covers automatic climate
 
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simonr66

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1992 W124 300TE
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W124 Heater Demist

Thanks hotrodder for clarifying my confusion - all makes sense now!

Will dig around the console in the weekend - hopefully the issue is at the front not the back!
 
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