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 07-08-2012, 03:13 PM
Registered User
 
Join Date: Apr 2012
Posts: 12
w124 blower motor inop

Hi everyone. Today my blower motor decided to take a crap, the compressor still spins, but the fan will not work at anyspeed. I assumed the worst so I removed the motor and tested it. It works fine. Finally I checked the firewall connections. I'm not getting12v at the firewall connector or at the 30amp fuse strip (which is good btw). What gives? What provides the 12v to the firewall connector?

Sorry everyone 1987 300d

Reply With Quote
  #2  
Old 07-08-2012, 05:36 PM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
EPC

No Charge to U.S. Residents.
(They will ask for a US based CC to prove you're their customer.)

EPC-net Online - Subscription Step 1 of 3

The Startekinfo site has the service CD s online.

___________________________________________________________________
"Quick and Dirty"
Do an Advanced Search (On this Forum)using Arthur Dalton's name as "Member".
He's dealt with all these Blower solutions,in multiples.
___________________________________________________________________
As In:
Here's your assigned reading for the rest of the Weekend.
PeachParts Mercedes ShopForum - Search Results
Attached Thumbnails
w124 blower motor inop-screenhunter_01-jul.-08-17.53.jpg  
__________________
'84 300SD sold
124.128

Last edited by compress ignite; 07-08-2012 at 05:53 PM.
Reply With Quote
  #3  
Old 07-08-2012, 05:56 PM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
But, this is the Electron Path you want

(As Always, Thanks Arthur!)
Attached Thumbnails
w124 blower motor inop-screenhunter_02-jul.-08-17.55.jpg  
__________________
'84 300SD sold
124.128
Reply With Quote
  #4  
Old 07-08-2012, 06:00 PM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
Also

http://www.peachparts.com/shopforum/tech-help/241868-95-e320-no-blower-speed-ccu.htm

[The 30Amp Aluminum Fuse @ the Strut tower (Driver's side) Looks can be deceiving !]

30A fuse feeds the Red wire @ the Firewall and if the fuse has a "Micro" (Almost invisible) crack ,no Power
@ red wire.
__________________
'84 300SD sold
124.128
Reply With Quote
  #5  
Old 07-08-2012, 07:26 PM
Registered User
 
Join Date: Apr 2012
Posts: 12
BTW, I also replaced the ignition switch 2 weeks ago.
Reply With Quote
  #6  
Old 07-08-2012, 07:36 PM
Registered User
 
Join Date: Apr 2012
Posts: 12
Ok, just in case I wasn't clear (because I probably wasn't). Fan stopped working today. Ipulled the fan out and tested it by going direct to batter and it spins. I found that the firewall fuse had 0 volts on either side. I found that the firewall conenctor to the fan has 0 volts to the black and red wire. The yellow (which I assume is the signal from the HVAC unit) has some voltage nowhere near 12v. IF I disassemble the connector, plug the yellow wire into the firewall connector and give the black and red seperate ground and +12v my volt meter shows anywhere from 11-12v (depending on high/low selection) at the fan connection. About two weeks ago I replaced the ignition switch with a beck arnley unit.
Reply With Quote
  #7  
Old 07-08-2012, 08:45 PM
engatwork's Avatar
Registered User
 
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 13,648
Quote:
[The 30Amp Aluminum Fuse @ the Strut tower (Driver's side) Looks can be deceiving !]
Totally remove the above fuse and see if it stays in one piece. If it does not then you have found your issue.
__________________
Jim
Reply With Quote
  #8  
Old 07-08-2012, 08:48 PM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
Second Line

in reply #3

"Battery/Ignition Switch/F15-30Amp fusible Link/RED wire of firewall connector."

1.Arthur is your "Guide".
2.I've "Schooled" myself,in almost Pavlovian Fashion,to Only accept Empirical
results in Testing.(Provable,Repeatable/Infinitely)Through my own "Assumptions
Proving Incorrect and therefore a self concealed Trap to diagnosis.
3.YOU may have replaced the Ignition Switch (correctly) or had a "Wrench"
replace it for you(Possibly Incorrectly).Or the Ign. Sw. MAY be bad.I don't
know and it doesn't matter.

Testing is simple in this instance:
1.12V (Or whatever "Battery Voltage" reads) @ the Pos + Neg poles of the Battery ?
2.12V at the appropriate terminals @ the Ignition Switch ?
3.12V at the Red And Black terminals of the "Firewall" connector?
If 12V NOT present @ the required location,THEN you have to look
at the WIRING as a possible culprit,IF 12V IS present ONE STEP Back.

We usually avoid testing the Ign. Sw. in this instance if at all possible,
'Cause it's such a Pain to get to.AND Instead use the Firewall Connector
as a Surrogate.(If Voltage is present @ F.C. ...If MUST be present at the
Ign. Sw.)

The Yellow Wire @ the F.C. has it's VOLTAGE changed Up and Down by the
C.C.U. (Climate Control Unit) as a signal device to the Regulator for Blower
Fan SPEEDS.

The Wiring diagrams and schematics are always a great help to me in visualizing
the circuits.[on the Factory Service Manuals]
__________________
'84 300SD sold
124.128
Reply With Quote
  #9  
Old 07-09-2012, 11:33 AM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
So

What was the Problem ?

Thanks!
__________________
'84 300SD sold
124.128
Reply With Quote
  #10  
Old 07-09-2012, 12:03 PM
Registered User
 
Join Date: Apr 2012
Posts: 12
Quote:
Originally Posted by compress ignite View Post
What was the Problem ?

Thanks!
Well my new ignition switch has failed. There is no continuity between either of the #30 connections (which is constant 12v) and 15x (which apparently is what goes throught the 30amp fuse and fan connections). Now if I could only source a decently price ignition switch that isn't BeckArnley.....

On the positive side it now only takes me 1 hour to r&r the ignition switch. Hint, I superglue the screw onto a little straight screw driver and start with the upper screw hole first.
Reply With Quote
  #11  
Old 07-10-2012, 10:46 AM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
No, Thank You!

"On the positive side it now only takes me 1 hour to r&r the ignition switch. Hint, I superglue the screw onto a little straight screw driver and start with the upper screw hole first."

This is the Kind of Battlefield short cut that you only "See" if you're in the Trenches.

__________________
'84 300SD sold
124.128
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 09:23 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page