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-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 02-13-2011, 07:48 AM
Registered User
Join Date: Feb 2011
Posts: 1
W124 Climate Control Issues


I just got a '93 300E 2.8 for a song. It's in great shape (just a couple of minor fixes) except for the climate control. I get no response when pushing any of the buttons or turning the temp control. The blower come on and the compressor doesn't kick in.
1. How do I begin troubleshooting the system?
2. Where can I find a FSM?
3. Barring that, is there any service manual available?

This is my first Mercedes and I could use any help at all.


Reply With Quote
Old 02-13-2011, 02:44 PM
babymog's Avatar
Loose Cannon - No Balls
Join Date: Jan 2006
Location: Northeast Indiana
Posts: 10,767
Start out by checking fuses, sometimes they are blown and sometimes they are not making good contact. Also there is a separate strip fuse in a black plastic holder bolted to the driver's side strut tower top.

Gone to the dark side

- Jeff
Reply With Quote
Old 02-14-2011, 08:26 AM
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
Since the BLOWER works, most likely issue isn't a fuse.

The compressor is controlled by a compressor (KLIMA) relay.
That relay gets signals from a/c pushbutton & sends command signal to the klima relay.
That relay gets RPM signal & refrigerant fill message & then turns on the compressor.

How good are you volt meter skills?
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
Old 02-14-2011, 10:12 AM
Registered User
Join Date: Jun 2000
Location: Plano, TX
Posts: 2,531
There is a detailed troubleshooting flowchart in the climate manual. It specifies use of a special tool for checking the climate system. The tests can be run using a simple DVM, if you are willing and able to simultaneously read the wiring diagram. It's a lot of work.

You haven't specified whether you are trying to heat or cool the cabin - it makes a difference. Since you're using USA model nomenclature, I'll assume the former. Try the simple test in the following paragraph.

A simple place to start - try unplugging the auxiliary electric water pump. It is located (I think...varies a bit on different 124 models) in front of the battery, with the monovalve. There is a connector on the pigtail that can be undone. The pump tends to short out after a dozen or so years, which causes the climate control pushbutton unit to go into a protection mode that more or less is what you've described.
Reply With Quote
Old 02-14-2011, 10:57 AM
babymog's Avatar
Loose Cannon - No Balls
Join Date: Jan 2006
Location: Northeast Indiana
Posts: 10,767
Originally Posted by mbdoc View Post
Since the BLOWER works, most likely issue isn't a fuse
I'm not sure since the post says he gets no response from pushing buttons, but also says "the blower work"? Figured I'd cover the strip fuse also.


Gone to the dark side

- Jeff
Reply With Quote


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 06:55 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, 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