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

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 04-25-2009, 06:56 PM
apb apb is offline
Registered User
 
Join Date: Mar 2001
Location: Houston, Texas
Posts: 447
97 E420 (W210) Aux Fan problem

My aux fan is not working. I tested the connector with the engin really hot (approaching 115-120) and my test light blinks every 5 to 6 seconds without the motor engaging. Any clues? Is it a relay issue? strange the it would be at a regular interval.
Thanks for you help and thoughts. I have not tested the motor yet, but it appears to be a power supply issue...
__________________
1997 E420
2005 CLK500 (conv)
2010 GLK350
Reply With Quote
  #2  
Old 04-26-2009, 10:12 AM
Registered User
 
Join Date: Nov 2005
Location: Cross Roads, PA
Posts: 324
With engine running hold both AUTO buttons down on the Climate Control system for over 10 seconds. This should put the AUX fans in HIGH SPEED mode. If not it could be the fans are just worn out. Also, the one on the passenger side is belt driven from the main one on drivers side. If the belt broke, it could be impeding the fan from turning. If you get a replacement online, becareful, the tend to be wired incorrectly. Its no big deal, you just take apart the connector and switch the wires. I had this problem last year, couldnt figure out why the fans were turning backwards.
__________________
Dennis
2006 E320 CDI Black/Black Leather. Nav, HTD Seats HK stereo 32000 miles.
2000 VW Passat 1.8t 300,000 miles as of Dec 09, 2009 original owner
1997 E300d Silver 300,000 miles As of Jan 05, 2010
3rd owner SOLD
Reply With Quote
  #3  
Old 04-26-2009, 02:21 PM
Registered User
 
Join Date: Sep 2004
Location: DFW / Collin County Texas
Posts: 1,882
Quote:
Originally Posted by e300D97 View Post
With engine running hold both AUTO buttons down on the Climate Control system for over 10 seconds. This should put the AUX fans in HIGH SPEED mode. If not it could be the fans are just worn out. Also, the one on the passenger side is belt driven from the main one on drivers side. If the belt broke, it could be impeding the fan from turning. If you get a replacement online, becareful, the tend to be wired incorrectly. Its no big deal, you just take apart the connector and switch the wires. I had this problem last year, couldnt figure out why the fans were turning backwards.
Ditto on the reverse polarity of aftermarket fan units. I dealt with that on mine and couldn't figure out why the A/C kept venting refrigerant out the check valve. Hooked up the gauges and saw 400+ PSI!!! Reversing the polarity via the connector as stated resolved the issue, but now my A/C compressor is a little noisy. It's too bad, because the compressor was probably a year old (new, not reman) when this happened.
__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280
Reply With Quote
  #4  
Old 04-26-2009, 02:25 PM
Registered User
 
Join Date: Oct 2005
Posts: 4,263
Do you have an aftermarket fan assembly? I had one of these fail on me after nine months of use, and it failed with your exact symptoms. It was also wired in reverse, but that had been fixed.

The fan controller is much more than a simple relay and resistor. It pulses the motor (the pulses that you saw) to start it, and reads the electrical signature of the motor during these pulses. If the signature is wrong (say, your cheap aftermarket fan motor magnets have weakened), the fan fails to start, and another attempt is made in a few seconds. If the motor bumps during this attempt, give it some help (spin the hub with your hand) to see if it will start. If the motor is going bad but not all the way gone and the controller is good, this may start it up.

Note that testing whether the fan runs with 12V applied is not a valid test of the controller. Mine ran just fine (but not as strong as new) with 12V applied, but the new OEM assembly did cure my problem.
Reply With Quote
  #5  
Old 04-27-2009, 12:52 AM
apb apb is offline
Registered User
 
Join Date: Mar 2001
Location: Houston, Texas
Posts: 447
I have the original fan motor, about 12 years, looks like it is shot... if will not start with the initial current... I will try to find a replacement motor...
__________________
1997 E420
2005 CLK500 (conv)
2010 GLK350
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 07:03 PM.


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