Rear vents blowing very hot air when A/C is on (already replaced heater controlvalve)
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
Rear vents blowing very hot air when A/C is on (already replaced heater controlvalve)
My 2004 E55 is blowing very hot air from the rear vents when the AC is on. I replaced the heater control valve under the wiper motor and still have the issue.
Any ideas what else it could be?
Any ideas what else it could be?
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
It appears to only be happening if the car gets very hot after sitting in the sun. Could it maybe be a shot interior temp sensor? Has anyone experienced that?
Also, where is the SAM located that controls the heater valve?
Any help is really appreciated.
Also, where is the SAM located that controls the heater valve?
Any help is really appreciated.
Last edited by moehler; May 9, 2015 at 09:53 AM.
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
It fluctuates. It may be fine for 20 minutes, then it blows hot again. Once the rear vents blow hot, they will keep blowing hot for a while. Sometimes I can get it to recover by screwing the with the temp settings, or restarting the car.
It always (I believe) blows hot when max AC is on... I haven't 100% proved this yet, but I believe it to be true.
It always (I believe) blows hot when max AC is on... I haven't 100% proved this yet, but I believe it to be true.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
MBWorld Fanatic!
Joined: Apr 2012
Posts: 1,274
Likes: 38
From: Seattle
2008 Mercedes Benz E63
I'm working on one at work. I'm thinking it is the blend door motors failing. I have the head unit out right now to monitor them after the car runs for 20 minutes to see what they are doing.
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
MBWorld Fanatic!
Joined: Apr 2012
Posts: 1,274
Likes: 38
From: Seattle
2008 Mercedes Benz E63
I'm working on a CLS. I removed all the trim around the shifter with the boot and knob, then the head unit, but to actually remove the motors is going to be a *****. Right now I have it apart just to see what is happening. Actually removing the motors is going to be a different story. The dash may need to come out.
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
I'm working on a CLS. I removed all the trim around the shifter with the boot and knob, then the head unit, but to actually remove the motors is going to be a *****. Right now I have it apart just to see what is happening. Actually removing the motors is going to be a different story. The dash may need to come out.
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
Seriously! The last dash I pulled was a serious pain, seats steering wheel, etc. I can only imagine that the electrical connectors are a mess in this car... At this point, I hope layzie finds nothing wrong with the motors! 
.
I know this is a complete stretch, but is there any chance it's the multifunction, or possibly the humidity sensor? My temp sensor seems fine (I used the hidden features to verify its reading correctly). If not, I guess it's down to the SAM or actuator motor...
. I know this is a complete stretch, but is there any chance it's the multifunction, or possibly the humidity sensor? My temp sensor seems fine (I used the hidden features to verify its reading correctly). If not, I guess it's down to the SAM or actuator motor...
Member
Joined: May 2014
Posts: 211
Likes: 3
2006 E55 AMG
I work for Honda. We have had issues with a resistor in center console that runs power to rear control unit. Resistor fails and rear center console vents blow hot. Don't know if our cars have that or not.
MBWorld Fanatic!
Joined: Oct 2011
Posts: 2,279
Likes: 27
From: A to the Z (the state)
'06 E55
Think about any extra wiring you want to do while the dash is apart, if you have to do that. Phone chargers tapped into keyed 12V, speaker wire/RCA cables for a future head unit swap, etc.
And, if you have to do this, take tons of pictures! Then make a kick-*** DIY thread.
And, if you have to do this, take tons of pictures! Then make a kick-*** DIY thread.
Thread Starter
Senior Member
Joined: May 2014
Posts: 350
Likes: 17
From: New Jersey
2014 CLS 63 S AMG / 2004 E55 AMG
