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
  #1  
Old 05-26-2012, 12:16 AM
Registered User
 
Join Date: Feb 2012
Location: North Central South Dakota
Posts: 4
Heater/AC

I have a 1983 300D. My AC works if I rotate the wheel all the way to the detent for AC. My heater seems to be on full heat in any other position on the temp wheel. So I seem to have heat on full at any position on the temp wheel except the max ac. At the max AC detent position the AC seems to work fine. Why cant I adjust heat.

thanks for any help
Reply With Quote
  #2  
Old 05-26-2012, 12:38 AM
Registered User
 
Join Date: Sep 2004
Posts: 8,429
Except in either (min or max) temp selector detent position, the control of the monovalve is in the hands of the electronic unit for temperature control. Evidently, you have a problem in that circuit. The "min" detent provides a constant ground path to the monovalve (except in defrost) which keeps the valve closed.
__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.
Reply With Quote
  #3  
Old 05-26-2012, 01:25 AM
Registered User
 
Join Date: Feb 2012
Location: North Central South Dakota
Posts: 4
Ok Im pretty much a newby to Mercedes as this is my first and I have only owned for a couple of months.
I think I know what the monovalve is. Mounted on firewall under hood behind engine.
However can you help me out with the electronic unit for temperature control. Is this the wheel itself?
Reply With Quote
  #4  
Old 05-26-2012, 01:41 AM
Registered User
 
Join Date: Sep 2004
Posts: 8,429
The electronic unit for temperature control is located near the glove box, under the dashboard. The problem, however, is not necessarily with the electronic unit itself. High on the list of possible culprits would be failed solder joints in the push button unit.
__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.
Reply With Quote
  #5  
Old 05-26-2012, 12:06 PM
Inna-propriate-da-vida
 
Join Date: May 2008
Posts: 1,885
Resoldering every solder joint on the circuit board of my SD made all the difference. Only takes about an hour to remove/repair/replace.

Now that works, I'm actually tempted to try and get the AC functional.


Maybe start with this thread -
DIY page. Introduction to Resoldering Climate Control Unit
__________________
On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif
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 07:34 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page