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 > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-22-2001, 03:41 PM
arochard
Guest
 
Posts: n/a
Just started to get really hot here in T.O. and I've noticed that my auxillary fan doesn't seem to come on when hot. Not that my engine is overheating or anything, but it used to come on when idling too long at a traffic light or something. The fan kept blowing a fuse last year and when I checked the wires, they were all frayed and chewed up. I then cut out the destroyed part, re-connected the wire (shortened) with butt-connectors and the fuse doesen't blow now although the fan doesn't seem to be working now.

I have checked it and it moved freely (manually)can the relay be blown ?

Any other ideas ?

Thanks,

AARON ROCHARD

1976 230.4 W115


Reply With Quote
  #2  
Old 06-22-2001, 06:12 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
The large temp switch on the thermostat housing grounds the wire at 212 deg F. Take the wire off the switch and ground it; the fan should work.

The fan should also come on when the refrigerant in the A/C gets hot. The switch for this is one the drier at the firewall/pass side. Connect the two wires together and the fan should run.
__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
Reply With Quote
  #3  
Old 06-22-2001, 08:30 PM
dlswnfrd
Guest
 
Posts: n/a
Pressure switch not temperature

Brother of the Benz, arochard
On the W124030, 300E, the switch stevebil is referencing is the red one on the drier/receiver and it is pressure sensative not temperature.
If your W115 230 is similar then jumpering the two wires should start the aux fan.
Happy Trails Beep Beep from The Spiderman in Houston!!!
Reply With Quote
  #4  
Old 06-22-2001, 09:39 PM
Registered User
 
Join Date: Mar 2001
Posts: 326
Test the fuse and make sure is has power.
You can apply power directly to the aux fan to make sure it does run.
As Steve suggested ground the 212F switch and by pass the high temp switch on the receiver drier (Yes Spiderman, this swicth is a temp switch unlike the new ones we have ).
Check the freon level in the A/C system also.
HTH
__________________
Scott Diener
89 300E
93 300E
92 Volvo 740 Wagon aka "Mutt mover"
Reply With Quote
  #5  
Old 06-28-2001, 02:30 PM
arochard
Guest
 
Posts: n/a
Thanks guys. The first thing I'm going to do is try a more powerful fuse. I checked in my Aux. fusebox last night and noticed that I have a 16A fuse in there and as I recall, the car came with a 25A one in there. I must have changed it while trying to figure out my original problem. Does this sound right to you all?

AARON ROCHARD

1976 230.4 W115
Reply With Quote
  #6  
Old 07-09-2001, 06:47 PM
arochard
Guest
 
Posts: n/a
It's Alive !!!!

Tried changing the fuses on the aux fan and nothing happened. Then I grounded the wire attached to the temp. sensor to the thermostat housing and Voila... the fan works. Now will the fan continue to work or does this mean that I need a new switch or something. Not sure where to go from here.

Thanks all,

AARON ROCHARD

1976 230.4 W115
Reply With Quote
  #7  
Old 07-09-2001, 08:36 PM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
OK, here's my prob...

along these lines.

Noticed the temp climbing in traffic yesterday. OK when underway, get home and the aux fan isn't running. I tried grounding the temp switch wire, and all I get is a clicking sound coming from the passenger firewall area. Sounds like the relay is trying to kick in, but no fan.

I did not disconnect the A/C switch in this equation. Should I have?

Also, working solo, I can't tell which relay is clicking. There are three in the area of the pass firewall, two round ones flanking a square one. Which is the likely relay?

Now, I'm off to squint at the wiring diagram some more.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #8  
Old 07-09-2001, 11:07 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
Gotta watch out on them 108 cars. The fan had a hood switch to keep to family jewels safe.
__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
Reply With Quote
  #9  
Old 07-10-2001, 02:47 AM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
Yeah, the spinnin' part does look a mite close when leaning in the engine bay . Where is the hood switch located? I don't recall seeing any switch buttons.

The suspect relay, the square one (I still haven't been able to feel it when grounding the switch wire), is part # 001 542 02 19. Looking at relays in PartsShop, I find a 001 542 22 19, which is labeled a "5 pin changeover". I assume this is simply an updated part number. Is this the aux fan relay?

Could I also check the temp switch with an ohm meter? I'm thinking if it grounds at 212dF, I should see continuity between the post and the block when it hits 212.

After pouring over the wiring diagrams this evening, I'm thinking I need reading glasses. All them little line just kind of ran together after a few minutes . Ah, the joys of getting older.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #10  
Old 07-11-2001, 01:27 AM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
OK, after looking at the diagrams, I find a reference to the safety switch Steve talked about (pin 49 at the 5 pin changeover), however, I find no switch. This 5 pin replay is the relay that was clicking yesterday.

Today, I disconnected the single wire from the temp switch as well as both leads coming off the A/C switch. Upon grounding the single lead to the block, the fan kicked on and remained running after ungrounding it. I had to turn the key off to stop the fan.

Next I jumped the two leads that attached to the A/C switch, again the fan ran. Again, I had to turn the key off to stop the fan.

With both switches disconnected I started the engine, kicked on the A/C and attached an ohm meter to the A/C switch leads and the single post of the temp switch. At approximately 195dF the A/C switch made contact. The 212 temp switch did not make contact until the gauge was nearing the red.

Can a bad 212 switch affect operation of the A/C temp switch and keep the fan from coming on, or are they independant?

Last thing I checked was continuity of the leads going to the fan from the A/C switch. With the meter set to 200K and one lead to each wire I showed 0.6 when I expected full resistance (0.0). Checking the wires individually to ground, one wire reads 0.0 the other reads 0.6 (I don't remember which was which).

Does this sound right or does it sound like the fan motor has started south?

With the daily temps hitting the low 100's, I really need to get this sorted out quickly.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #11  
Old 07-26-2001, 02:02 PM
DBarrybish
Guest
 
Posts: n/a
I've got a 72 280SE - she's overheated since I got her. Have you solved your axillary fan problem? Mine use to come on as soon as the car was turned on, it doesn't appear to come on at all now, something I've told the mechanics, but they insist it is only for the AC, and shouldn't make a difference with the temp if the AC is off. I peg out on the temp gauge during the summer if I'm not moving. Is the axillary fan for more than just the AC?
Reply With Quote
  #12  
Old 07-26-2001, 05:24 PM
G-Benz's Avatar
Razorback Soccer Dad
 
Join Date: Apr 2001
Location: Dallas/Fort-Worth
Posts: 5,711
I'm not sure myself, but I'm having overheating problems on my W124 too, and they seem to be related to the A/C...in other words, temps are normal when A/C not running, when A/C is on, and (I suspect) aux fans not doing their job, temps start climbing.

I can actually get my aux fans to fire up simply by disconnecting the two-prong lead from the thermostat housing. Did that last night as a test, and let them run for the entire trip home. Despite the 103 temps outside and A/C at max, engine temp remained between 85-87 all the way home, highway-city combo driving! So my guess is that they are not coming on early enough, or not at all!
__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
81 300SD heater fan, etc, not working maximumbob Diesel Discussion 1 11-30-2004 05:23 PM
Auxiliary fan not working Rick-300E Tech Help 4 11-17-2004 09:26 AM
Auxillary Fan Temp Sensor Troubleshooting Motor Head Tech Help 0 08-05-2004 11:39 PM
Auxillary fan Kodiak Tech Help 3 08-07-2001 01:38 PM
Auxillary fan info on CD?? Kodiak Tech Help 0 08-06-2001 01:50 PM



All times are GMT -4. The time now is 04:29 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page