Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #16  
Old 04-19-2011, 03:09 PM
nomorehurry's Avatar
Registered User
 
Join Date: Dec 2007
Location: Abilene, Texas
Posts: 115
Quote:
Originally Posted by tangofox007 View Post
"Now" is how I read it. The difference would be in how the air is distributed, not in the temperature of that air. I don't think the uncommanded heat problem is in any way related to the defrost air distribution..
With the defroster, what I found was that cool air was comming from the defroster vents to the in-car temperature sensor. The sensor read the cool air and sent an incorrect message to the CCU (car is cold - turn on heat). Result, heater came on until in-car sensor told CCU that car was too hot. Unfortunately the car had to be stopped to allow something to reset and go back to cooling mode.

Anyway, it did have to be fixed and only cost $10 (U-pick part) and some bad words to get it installed. However, experience from the u-pick place in taking the vent control out was of great help in putting the new (old but working) part in.

Now the system seems to be OK except that this morning the air conditioner stopped and sent slightly warm (not hot!) air to the cabin instead of the cooled air. After allowing the car to rest for a while, everything went back to normal and stayed that way until I god home, which was a longer trip. I'm thinking that might be the high temperature shut down for the compressor, which I think has already been replaced once.

If the d*** machine would be consistent, it would be a lot easier to trouble shoot. (the word "shoot" is starting to sound better the more I work on this thing. )

PS: In case I didn't say it before, I appreciate your assistance.
__________________
Better, Faster, Cheaper, pick two.
Reply With Quote
  #17  
Old 04-19-2011, 03:27 PM
Registered User
 
Join Date: Sep 2004
Posts: 8,344
Quote:
Originally Posted by nomorehurry View Post
With the defroster, what I found was that cool air was comming from the defroster vents to the in-car temperature sensor. The sensor read the cool air and sent an incorrect message to the CCU (car is cold - turn on heat). Result, heater came on until in-car sensor told CCU that car was too hot.
The temp sensor should not be a factor in the "defrost" mode. The ACC should engage the compressor and provide maximum heat, regardless of temp selected.

Quote:
Originally Posted by nomorehurry View Post

Now the system seems to be OK except that this morning the air conditioner stopped and sent slightly warm (not hot!) air to the cabin instead of the cooled air. After allowing the car to rest for a while, everything went back to normal and stayed that way until I god home, which was a longer trip.
That sounds a lot like a faulty evaporator temp regulator.

Quote:
Originally Posted by nomorehurry View Post
I'm thinking that might be the high temperature shut down for the compressor, which I think has already been replaced once.
The original configuration had no such feature.
Reply With Quote
  #18  
Old 04-19-2011, 05:33 PM
nomorehurry's Avatar
Registered User
 
Join Date: Dec 2007
Location: Abilene, Texas
Posts: 115
I agree that you should get full heat in the defrost mode.

However, I was in the regular central vent (button 3) mode and should not have had any flow through the defroster vents. But I was still getting cold air that would fog the inside of the windshield (given more than the 9% humidity in west texas). Thats why I think it was the air cooler flow from the defroster vents that led to incorrect information to the CCU.

I guess I didn't make the situation clear earlier.
__________________
Better, Faster, Cheaper, pick two.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 06:29 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page