E30 M3 Fan Resistor
Printed From: Bavarian-Board.co.uk - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: BMW ///M Power
Forum Discription: Ask your BMW M Power Technical Questions here (M1, M2 hybrids, M3, M5 & M6)
URL: http://www.bavarian-board.co.uk/forum_posts.asp?TID=23194
Printed Date: 16-June-2024 at 15:18
Topic: E30 M3 Fan Resistor
Posted By: Zainwq
Subject: E30 M3 Fan Resistor
Date Posted: 16-October-2005 at 16:36
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Hi all Im new to all this, so would appreciate a little help from you fellas. My brother uses this quite a lot, rezaq. Anyway, Ive just bought a lovely E30 M3, on a H plate, 1 UK owner. I love it. But, the low speed fan didnt cut in, and with the help of this forum we discovered I had to change the resistor which sits on the fan housing. I changed this, and everything was perfect. Then, nothing, dead again. Ive discovered the resisitor, which I had to tie wrap onto the bottom of the fan housing as the screws on the old resistor where seized shut, had heated up so much it melted the plastic tie wrap and the area it was sitting in. I am guessing its overheated and burnt out, great £30 invested there, so what Ive done is just bypassed it, and hard connected the connections. Seems to work fine now, cuts in, both high and low speed. The fuse now needs to be 20amp though, as opposed to the 15amp which then couldnt handle the new resistor bypass. Any ideas what this resistor did? Regulated the power? Any harm with this new set up? The high speed cut in uses a 30amp fuse, so this 20amp wont exactly burn out the fan will it? Thanks Zain. |
Replies:
Posted By: Codhead
Date Posted: 17-October-2005 at 04:47
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The resistor always heats up, that is why it is situated at the front and has vents on it to cool it. Have you checked all your wires it shouldn't burn out like you said it does. Don't know whether wiring it like you have done will lead to any permanent damage though hopefully someone else will chip in there 2 penneth.
cheers |
Posted By: Jim M3
Date Posted: 17-October-2005 at 05:31
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Zain, I had this exact same problem! After changing that resistor about 4 times Jim. |
, I have decided to put an aftermarket fan on mine as soon as it is back on the road. The high speed fan will still come on at about the 3/4 mark but I wasnt entirely happy with this. I shall probably go down the Kenlowe root with an adjustable thermostat. Good look in sorting.Posted By: Zainwq
Date Posted: 18-October-2005 at 08:21
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Did your resistor keep blowing Jim? Any ideas why? Did you mount it where it wasnt designed to be aswell?? Adjustable thermostat. Sounds interesting Does anyone know anything about these ballast resistors? |
Posted By: Jim M3
Date Posted: 18-October-2005 at 09:37
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Zain, Yes kept getting red hot then breaking. I had it checked out by an electrician who couldn't sort it. It was mounted in the correct position behind the centre grille (as far as I am aware) Just out of interest, does anyone on here have an aftermarket fan on their car. Any other ideas other that Kenlowe? |
Posted By: bmwe21
Date Posted: 19-October-2005 at 03:17
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If it gets red hot I think the fan itself might be up for a
replacement. Sometimes they do that or just get stuck right away. But
in 99% of the cases the fans don't give any trouble (just the
resistors) so I see no reason to fit some aftermarket fan. ------------- Rgds, Jeroen http://www.bmwe21.net - www.bmwe21.net E21 323i - E30 320iS - E30 325i track car |
Posted By: Rob L
Date Posted: 19-October-2005 at 03:45
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Zain, If you have now bypassed the resistor then your fan will probably be running at higher speed for both low and high speed circuits as there is nothing inline to reduce the power. Now that you have changed the fuse to 20A it cant blow, if you replace the resistor again it will once more be overloaded and therefore melt. Fuses are there for a purpose and protect the circuits from damage - at the end of the day it's blown and it's telling you something isn't working as it should. I would look into buying a new fan, make sure you have replace the 15A fuse on the low speed and check a 30A fuse on is fitted on the high speed and you should be ok. ------------- 1990 E30 M3 Sport Evolution |
Posted By: AndyS
Date Posted: 19-October-2005 at 13:34
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The low speed resister on my 635 is currently kaput too. Normally it
doesn't matter but it got very hot & bothered in traffic during the
summer. Getting onto the NE stand at Gaydon was more exciting than it should have been too! Must get around to changing it. ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow"> 
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Posted By: Zainwq
Date Posted: 19-October-2005 at 18:21
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Cheers rob. That makes sense. Although I swear the low speed fan is correctly running at low speed, you can feel the high speed one a mile off. Seized fan sounds right too. Ive only had the car a few weeks, before that it was in storage for 6 months, and the fan had to be manually freed because it wouldnt cut in, it was in fact slightly seized. If I keep the set up like this, whats the worse that can happen? Fan will burn out? After how many hrs use you reckon? Everythings sweet right now. Zain. |
Posted By: Rob L
Date Posted: 20-October-2005 at 04:49
Zain I guess you forgot to mention that the fan was seized in your first post. If that was the case then it's obvious that your fan is dead. If you choose to bodge it for now then it all depends on the circuit rating. The low could be the same as the high and be able to take 30A, but then it might not. If it's not you'll end up burning out the harness. It will probably run like this for a while but as the fan gets worse the 20A fuse will blow. If the the fan is definitely running at low speed then the motor has 2 separate coils (one for low, one for high), but the low also has the resistor fitted to drop the current. Who knows when the fan will die, that's your gamble dude! IMO I would do the job properly and buy a new fan. Alternatively make sure you've got rescue cover - chances are you'll burn out your harness, or more than likely the fan will sieze completely when you least expect it, then you will be in the creek.... ------------- 1990 E30 M3 Sport Evolution |
Zainwq wrote:Posted By: rezaq
Date Posted: 20-October-2005 at 07:02
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I did tell him then to do it properly.
Looks like the fan it is. Anyone know where the cheapest place for these is? |
Posted By: Zainwq
Date Posted: 20-October-2005 at 07:34
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Yes you did mate. C3 do it with the resistor for £180inc vat + delivery i think. do euro do them? |