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 01-29-2019, 09:12 AM
Registered User
 
Join Date: Jun 2008
Posts: 468
Auxiliary Water Pump Can Destroy CCU or Even Car?

The auxiliary water pump on my 81 380sl hasn't been working, so I just picked one up on Ebay. However, I learned from several threads on these pumps that, if the pump seizes and draws too much current, it could destroy the CCU or even the car, as it did in this thread:


I lost it all....electrical fire high up in the dash


So, I'm hesitant to install it without first putting a 1 amp fuse on the power wire out.


Can anybody tell me if that problem affected the 81 380sl and, if so, is it caused by particular pumps, the car's circuitry, or both.

Thanks very much in advance. __________________
1981 380SL
Chassis: R107.045
__________________
1981 380SL
Chassis: R107.045
Reply With Quote
  #2  
Old 01-29-2019, 09:18 AM
Diseasel300's Avatar
Registered User
 
Join Date: May 2016
Location: Texas Hill Country
Posts: 4,436
It affects all cars with the ACCII climate control system. 1980/81-1985. It's due to a design flaw in the pushbutton unit itself. The traces are not heavy enough to carry locked-rotor current to the pump and can overheat to the point that it damages the pushbutton circuit card, or if you're really unlucky, cause a fire. An inline fuse in the positive lead to the motor is cheap insurance.
__________________
'11 Honda Accord EX - "The Daily" 64K
'83 500SL Euro - "The Money Pit" 116K
'91 350SD - "The Diseasel Jr." 168K
'86 300SDL - "The Diseasel" 189K (Totaled 1/31/19)
The Diseasel Thread - Everything You Didn't Know You Wanted To Know
Reply With Quote
  #3  
Old 01-29-2019, 09:51 AM
Registered User
 
Join Date: Jun 2008
Posts: 468
Quote:
Originally Posted by Diseasel300 View Post
It affects all cars with the ACCII climate control system. 1980/81-1985. It's due to a design flaw in the pushbutton unit itself. The traces are not heavy enough to carry locked-rotor current to the pump and can overheat to the point that it damages the pushbutton circuit card, or if you're really unlucky, cause a fire. An inline fuse in the positive lead to the motor is cheap insurance.

Thanks a million for the quick reply. I replaced the "evil servo" with the digital unit some time ago, but your reply suggests that it won't make any difference.


After looking on line for a 1 amp fuse and fuse holder, the only one I could find was this one at Advance Auto parts:


https://shop.advanceautoparts.com/p/littelfuse-in-line-fuse-holder-0fny0030xp/11499021-P


I guess I can solder that into the power (black?) line. Problem is finding a 1 Amp fuse. Any ideas?
__________________
1981 380SL
Chassis: R107.045
Reply With Quote
  #4  
Old 01-29-2019, 04:09 PM
Registered User
 
Join Date: Dec 2006
Posts: 3,411
Depending on the vintage of the CCU, there may be a fuse conveniently located on the rear of the head unit. All you have to do is pull the dash apart to get to it. An inline fuse would be a good idea.
Reply With Quote
  #5  
Old 01-31-2019, 06:40 AM
Registered User
 
Join Date: Jun 2008
Posts: 468
Thanks for the info. Yes, putting a fuse in would obviously be preferable to taking a chance on there being a fuse in the head unit or, even, having to check for one.
__________________
1981 380SL
Chassis: R107.045
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 08:12 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, 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