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Registered
1991 560 SEC
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229 Posts
Discussion Starter #1
while driving, 70mph, and the windows about 1/2 down, the windshield defroster vents are pumping out super hot air and the button is set to off and the fan switch is on low.

what is going on?

is it a vacuum pod? and if so which pod controls the windshield defroster vents.

its not hot when the a/c is on.

thanks for the help
 

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Premium Member
2012 CL550 4MATIC Coupe
Joined
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9,992 Posts
Gary - Sounds like you may have a pod problem. You should read my AC Center vent thread and troubleshoot them to see if they are all good. The 'default' settings are for heat and defroster because Mercedes always defaults to the safety position. So if there was a problem and it failed, it would not go to cold and face vents. The safety position is heat and def. You would not want it to fail in winter and be blowing cold air on the windshield.

So review my thread and if you have any questions, PM me and I will be glad to guide you where I can.

LMK.
 

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Registered
1991 560 SEC
Joined
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229 Posts
Discussion Starter #3
there's more to add...the climate control buttons don't work. i switched out a working unit but nothing. there is a small difference in climate control part numbers. the donor part is 126 830 08 85 which comes from an 88 560 sec. the other part number is 126 830 11 85.

i recall once when trouble shooting my old sec regarding the climate control...when i pushed the a/c button you could audibly hear a switch under the hood turn on. that doesn't happen with either part.

is there an a/c relay and if so where is it on a 1991 560 sec?
 
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