318ti.org forum

Go Back   318ti.org forum > Technical, Maintenance and Modifications > Electrical

Notices

Electrical All wiring questions.

.
» Recent Threads
1999 M-Sport For Sale
12-31-2023 05:10 PM
Last post by Coop540iT
03-23-2024 06:39 PM
1 Replies, 99,085 Views
Once again 318ti owner...
03-20-2024 12:39 PM
Last post by two30grain
03-22-2024 02:04 PM
1 Replies, 62,014 Views
What brakes do I...
03-20-2024 03:27 PM
Last post by huirtera
03-20-2024 03:27 PM
0 Replies, 59,286 Views
Reply Share/Bookmark
 
Thread Tools Display Modes
Old 08-15-2013, 01:27 PM   #1
wake74
Senior Member
 
Join Date: Jul 2013
Location: Lakeland, FL
Posts: 229
iTrader: (1)
Default Fan Wiring - Wiring Low Speed & High Speed Together

Luckily, this isn't a competition against my car, as it is currently kicking my behind, as every area I look has some issue that was left unfixed by the previous owner.

My car has not over-heated while I have been driving it, even on very hot days. However, I noticed while letting it run in the garage the other night that it started to spit coolant out the cap. After digging into the electrical, it was obvious that low speed was not coming on for the fan. High speed works with AC, which is probably why it never over-heated even on the hottest days. I've already done the cooling system maintenance, bled repeatedly etc. Actually when I was bleeding it in the garage is when I first got it to over-heat and spit out coolant.

After much troubleshooting, it was obvious the issue is with the low speed circuit in the fan itself (presumably the resistor), as I get voltage at the low speed wire at the fan connector when shorting the correct terminals on the two stage temp switch on the radiator.

The really frustrating thing is that I just bought this fan as a good used fan, to replace the badly cracked one that came with the car.

Long explanation to ask a simple question: Is there any harm in just rewiring the fan motor to run a single speed, when it needs to run?

Thanks!
wake74 is offline   Reply With Quote
Old 08-16-2013, 05:19 AM   #2
pdxmotorhead
Senior Member
 
Join Date: Mar 2005
Location: Portland Or
Posts: 2,666
iTrader: (1)
Default

The fan is loud on high speed, and it will wear out , it does not really have a 100% duty cycle on high speed, it normally kicks on and off while running the AC so it does not overheat. Id get the new resistor pack its not that expensive..

Dave
__________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black
pdxmotorhead is offline   Reply With Quote
Old 08-16-2013, 12:36 PM   #3
wake74
Senior Member
 
Join Date: Jul 2013
Location: Lakeland, FL
Posts: 229
iTrader: (1)
Default

Dave - I was under the impression that the resistor pack was only available attached to a $300 new fan assembly. Do you have a link or part number? Thanks!
wake74 is offline   Reply With Quote
Old 08-17-2013, 06:00 AM   #4
pdxmotorhead
Senior Member
 
Join Date: Mar 2005
Location: Portland Or
Posts: 2,666
iTrader: (1)
Default

Darnit I cant find it,,,, Its just a heavy resistor, I swear someone posted the Radio Shack part number to replace the resister. It was either on here or M42.org..

Dave
__________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black
pdxmotorhead is offline   Reply With Quote
Old 08-17-2013, 08:38 AM   #5
John Firestone
Senior Member
 
John Firestone's Avatar
 
Join Date: Nov 2004
Location: Bremerhaven, Germany
Posts: 977
iTrader: (0)
Default

Here is the resistor pack shown in the 1995 ETM:



The value marked ".7" is most likely 0.68 ohms. I can't vouch for the accuracy of the values: as you might suppose from the ".7", the car was built from another set (or database) of drawings.

Last edited by John Firestone; 08-17-2013 at 09:06 AM.
John Firestone is offline   Reply With Quote
Old 08-17-2013, 12:15 PM   #6
wake74
Senior Member
 
Join Date: Jul 2013
Location: Lakeland, FL
Posts: 229
iTrader: (1)
Default

I am guessing by counting the wires and speeds that that wiring diagram above is for the interior blower not the aux fan on the radiator. I have the ETM and I don't recall it having any details on the aux fan resistor.

Can you confirm?
wake74 is offline   Reply With Quote
Old 08-17-2013, 12:33 PM   #7
John Firestone
Senior Member
 
John Firestone's Avatar
 
Join Date: Nov 2004
Location: Bremerhaven, Germany
Posts: 977
iTrader: (0)
Default

Right you are. I'm sorry, I read "resistor pack" earlier, and spaced.

You are after this attached resistor?


Last edited by John Firestone; 08-17-2013 at 12:46 PM.
John Firestone is offline   Reply With Quote
Old 08-17-2013, 12:44 PM   #8
wake74
Senior Member
 
Join Date: Jul 2013
Location: Lakeland, FL
Posts: 229
iTrader: (1)
Default

Right pic, wrong link. The link shows the blower motor one again. The aux fan resistor is a cigar shaped thing attached to the fan.

With the number of these that fail I am surprised no one has created a replacement to sell. I knew I should have paid more attention to that EE for non-EEs class I had to take in college many moons ago.
wake74 is offline   Reply With Quote
Old 08-17-2013, 12:59 PM   #9
John Firestone
Senior Member
 
John Firestone's Avatar
 
Join Date: Nov 2004
Location: Bremerhaven, Germany
Posts: 977
iTrader: (0)
Default

Here is something that might suggest a value. Two 1.5 ohm 50W resistors in parallel (to yield 0.75 ohm) and clamped to a mass of metal, would be what I might try.

Or on second thought, 2 x 1.0 ohm in parallel for 0.5 ohm.

Last edited by John Firestone; 08-17-2013 at 01:08 PM.
John Firestone is offline   Reply With Quote
Old 08-17-2013, 01:09 PM   #10
John Firestone
Senior Member
 
John Firestone's Avatar
 
Join Date: Nov 2004
Location: Bremerhaven, Germany
Posts: 977
iTrader: (0)
Default

Could something like this be the part? Not quite, but perhaps getting closer.

Last edited by John Firestone; 08-17-2013 at 01:12 PM.
John Firestone is offline   Reply With Quote
Old 08-17-2013, 03:30 PM   #11
wake74
Senior Member
 
Join Date: Jul 2013
Location: Lakeland, FL
Posts: 229
iTrader: (1)
Default

John - thanks for the help. That part is a bit different than OEM but is probably their solution to the low speed problem. $55 is one expensive resistor. Apparently if they have the only solution you can charge accordingly.
wake74 is offline   Reply With Quote
Old 08-17-2013, 03:43 PM   #12
John Firestone
Senior Member
 
John Firestone's Avatar
 
Join Date: Nov 2004
Location: Bremerhaven, Germany
Posts: 977
iTrader: (0)
Default

If someone could measure the resistance, you could probably make a repair or make up a replacement for less than half that, including shipping.

I would go take a measurement, but my auxiliary fan has a second low speed winding instead of the resistor.
John Firestone is offline   Reply With Quote
Old 08-17-2013, 09:45 PM   #13
pdxmotorhead
Senior Member
 
Join Date: Mar 2005
Location: Portland Or
Posts: 2,666
iTrader: (1)
Default

Here is a thread on teh same issue,,,
http://forum.roadfly.com/threads/169...C-on-fan-fixed

This is the one I used...
__________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black
pdxmotorhead is offline   Reply With Quote
Old 08-18-2013, 01:00 AM   #14
wake74
Senior Member
 
Join Date: Jul 2013
Location: Lakeland, FL
Posts: 229
iTrader: (1)
Default

Dave - Very good info in that thread. Which one specifically in that thread did you use? There were several listed between the thread and the links in the thread.

The ballast resistor for coil, seems like a good potential option as Rock Auto has that for a whole $1.29, but the sealed wirewound resistors are nice as well.
wake74 is offline   Reply With Quote
Old 08-18-2013, 07:04 AM   #15
pdxmotorhead
Senior Member
 
Join Date: Mar 2005
Location: Portland Or
Posts: 2,666
iTrader: (1)
Default

I used a big wirewound and screwed it to a old Processor heat sync.. with a couple tabs to hold it on the radiator..

Cheers
Dave
__________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black
pdxmotorhead is offline   Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
NO low speed fan signal Bills86e Electrical 25 08-09-2012 03:28 PM
Engine temp Q - 1996 318ti bazar01 I'm thinking about buying a ti. 33 09-30-2009 12:30 AM
Test if Fan Works? bmw318tiChic Electrical 62 09-25-2009 03:43 PM
High speed engine stutter and bog tomsTI Engine 9 03-19-2009 08:49 AM
2 Speed fan Relays Compact Missile General Chit Chat 9 02-08-2006 07:52 PM


All times are GMT +1. The time now is 08:39 PM.


.
Powered by site supporters
vBulletin Version 3.8.8
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©1999 - 2024, 318ti.org
© vBadvanced CMPS v3.2.2
[page compression: 111.83 k/134.71 k (16.98%)]

318ti.org does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information or products discussed.