[W126 Coupe] Centre AC vents

[Dick Spellman]

Centre AC ventsHi Barry:

If you always get air flow to the windscreen defrost vents that could well be the center vent/defrost flap vacuum element has failed.  If your 89 does not have a passenger air bag the r&r is fairly easy.  Just remove the interior of the glove box and reach up and in to the left to find the pink barrel shaped vacuum element with two vacuum lines attached at top and one mechanical lever attached at the bottom.

You should see this actuate and pull the rod into the barrel when you request AC on the climate control.  If you do not see this action then it's time to either repair the rubber diaphragms (2) inside or just buy a new one at MB for about $70.  There are two more elements in this same area to the right a bit and upwards that manage the fresh air/recirculation flap.  I'd replace or repair these at the same time.

There is a repair kit available from George Murphy for $45 that includes all of the rubber diaphragms needed for every element in the SEC except the floor element which is rectangular and requires a new one if you do not get heated air to the floor when heat is selected.

That's it.  I've simply ordered kits from George and rebuilt them on 3 MB's at this point.  Each takes about 10 minutes and you must be careful to mark the color for vacuum lines on the element and mark where the halves mate as well.  Last caution is to be patient in unclipping the halves so as to not break the brittle plastic fingers or the clips.

Air bag footnote.  If you have a passenger air bag accessing the center/defrost element is a bear because of the heavy metal frame that MB bolts in there to support the air bag.  It's still possible to get at it but, expect to curse a fair bit in the process.  The fresh air/recirc elements are tough too but, not as bad.

Regards,

Dick Spellman


  ----- Original Message ----- 
  From: Barry Sharp 
  To: mbcoupes at mbcoupes.com 
  Sent: Wednesday, August 03, 2005 3:39 PM
  Subject: [W126 Coupe] Centre AC vents


  Hi.  I need some HVAC expertise.  The centre dashboard vents have not worked since I've owned my 1989 Euro 560 SEC .  Neither warm air (which I understand is normal), nor cold air comes out of either centre vent.  I can hear a "clunk" when they are trying to work, and moving the centre direction lever moves the air between the upper and lower vents on the driver and passenger sides. 

  Any help would be much appreciated. 

  Thanks....Barry 

  1989 560 SEC Euro - 96,000 km 



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