I just bought the resister repair unit for my 04 ,just clip wires and reconnect .Fits like factory!

 

Chris made 1 heck of a discovery for the resistor fix that has helped many.
Here's the summary to the more than 30 long pages of this thread:

1. Those w/ 2 plug fan harnesses should remove the fan assembly & wire 2 leads onto the bad resistor's terminals for remote install of new resistor.

2. Those w/ single plug won't need to put car in service mode, no need to remove fan & gain access to the bad resistor. Only splice the new resistor to the big & small gauge wires on the fan side harness.

OR:

3.Cheapest simple performance oriented fix as described by Blwn on post#16 here:
https://www.northamericanmotoring.co...-resistor.html
You may opt for no resistor, cooler A/C & engine. Only if you value performance, & won't mind the 2nd stage's noise.

_______

 

For early 1st gens w/c the 2-socket harness, you can do the resistor delete or swap by:
1. Extracting the fan assembly.
2. Removing the burnt resistor.
3. Plugging & soldering onto the resistor terminals a looped jumper wire(12ga minimum) long enough to be routed to the location you might intend to put your optional new resistor in. When LOW is called, you get the HI noisy fan w/o the resistor. Some fear of blowing a fuse this way, but it's a simple rewire that should be more beneficial to your engine & A/C. Noticed operating engine temp w/ HI on LO to be about 3.5F lower on the Scangauge. With a resistor, your LO fan should be as stock.
4. Reassemble in reverse method.

Pics here:
https://www.northamericanmotoring.co...r-surgery.html

Disclaimer: mod at your own risk. These were experiments to find ways to tweak a faulty fan design w/o the expense. Always ideal to get a new OEM fan.

 

Hi all,

Newbie to this forum and to the Mini world.
Bought a 2002 Cooper S with 140000 kms on the clock and it has been very well looked after. This car is a run about for my wife around a small country town. I must say I can't get out of it myself.
The third day we had the car the serpentine belt let go, I had to go away for work and was going to inspect this when I came back but murphy's law won out.
The forth week my wife went into town to have lunch and when she came back after about 2 hours the battery was dead. I changed it over to a new one and all was good until one week later I found the cooling fan running on high speed after the car had been parked up for about 30 minutes. Hense the flat battery.
So I did some investigation and found this forum......can't speak highly enough of all the helpful tips. Very friendly/helpful members.
Further investigation into the problem and I to have no low speed fan and the high speed relay is also sticking in the on position now and again. I guess it is working harder as the low speed is not working. I do like the idea of bypassing the resistor and just having high speed on in place of the low speed as I live in a very warm tropical part of Australia. Tried to get a relay kit here in Australia but no luck I can only get the whole cooling fan unit for $250+.
I think I will get the relay kit, it cost $100 including shipment as I just can't seem to find one here in Australia and also change the relay for high speed and see how it goes. Thanks again very helpful site.

 

HI MINOZ, warm welcome to NAM. Bypassing the resistor gives you HIGH speed when LOW is called & doesn't get routed thru your sticking relay w/c is dedicated for the HIGH speed only. You probably won't have any relay-sticking after the bypass because ECU won't get temp sensor & A/C pressure signals to put high on anymore. Again, the only drawback is the noise of HIGH & probably a harder working, shorter life fan. Still way better than no LOW!

 

Hi MINSANITY,
I have been thinking a fair bit today about bypassing the resistor as where we are living we have the A/C on in the car for roughly 10 months of the year.
So I think it is a better option. While I am at it I am going to drop the coolant as I don't know when the last time it was done. Is there any coolants that I should stay away from?

 

Most of my friends are going the resistor-free route should they lose the low. Why prematurely replace a fan assembly w/ just a busted resistor when you can Squeeze the max out of the old fan, w/c is pretty reliable. On coolant, I use the blue BMW coolant concentrate. Isn't that pricey, really. Nitrate & Phosphate free, prevents aluminum oxidation. Depending on average freezing temps in your area, it has varying mixture ratios w/ distilled water. Been using it since I got the car. Never had to top off much. Best cooling agent is still distilled water, but the antifreeze is added to help prevent corrosion. If cooling system is perfectly working in a pressurized system like the R53, your coolant shouldn't even boil.
I'll PM you some more tips for our early R53s. We're getting a bit off topic here.

 

I know this thread is ridiculously long but this seems like the best place to post this question. I have skimmed through most of this thread but wasn't able to find my exact situation. Like many of us, the power steering is starting to die on my 2006 MCS (approx. 135K miles). So I am in the process of trouble-shooting.

My power steering fan seems to work as expected: When I turn on the AC, the PS fan fires right up. However, the low-speed radiator fan doesn't!

From my understanding of the info in this thread, the low speed fan should come on when the AC is turned on. From there, the PS fan is tied to the low-speed fan: When the low-speed fan comes on, it should trigger the PS fan.

Is it possible for the PS fan to come on WITHOUT the low-speed fan coming on? Does this point to a bad low-speed fan resistor?

Is the low speed fan ALWAYS supposed to come on when the AC is actived? Or is there a low-temp threshold where the AC compressor will not come on even if the AC is turned on. (Ambient temp was about low 50s in my garage when I tried this. On my other vehicle - an Audi - the compressor will not turn on if the ambient temp is below a certain threshold.)

(Since my PS fan is still working, I suspect my failing PS pump and apparently faulty low-speed fan are two isolated problems - both of which will be addressed when I figure out how these systems are supposed to work...)

 

Hello, Marquette MINI. Low speed fan is called together w/ your PS fan when coolant temp reaches 221F or when A/C system pressure reaches 8bar. If you've a busted resistor or a busted fan motor, then only a good PS fan will come on.
You'll know you have a good fan motor if you still get hi speed when A/C system pressure reaches 18bar or coolant temp reaches 234F.
Having a good PS Fan & a failing pump would be independent of your rad fan issues.
If you've hi speed, try the mod options in this thread to bring your low speed back.

 

Thanks for the reply. I do still have high speed fan operation. Last night I let the engine run with the AC on for a few minutes in the garage and the high speed eventually kicked on and cycled on and off for a few seconds each time. However, I saw no low-speed operation. PS fan works as expected (i.e. kicks on when AC is on without low-speed fan operation).

Will read back through this thread for how to mod the fan for low-speed.

 

Post 777 is a simple summary. You may splice a loop 12ga or bigger wire or add in a new external resistor.

 

I replaced my resistor with the mouser part a few months back. Over the weekend it incinerated itself while sitting at a light. Got a hint of something electrical burning then a bunch of smoke started coming out of the hood scoop. This whole design is terrible from the get go. Why BMW decided this was a good idea is beyond me.

Next step is I'm going to just bypass the resistor and have full speed all the time.

 

Wow - where did you have it mounted?

Would love to see a picture of the remains...

 

So I have a 2002 MCS which, if I remember correctly, was built in July.

My question is this: When should the low speed turn on or should it be on all the time? I have high speed that turns on the same time the PS fan comes and runs for a minute then shuts down but have not noticed any low speed on the radiator fan.

 

For 2002-2006 R50 MINI Cooper and R53 Coooper S Hardtops, and 2005-2008 R52 MINI Cooper and Cooper S Convertibles.

Thermostat:
Thermostat begins to open at 89-92° C (192° F - 198° F) and is fully open at 103° C (217° F).

Expansion Tank Cap:
Cap pressurizes the system to 1.1 bar (16 psi) at which point the cap valve will lift to relieve pressure.

Cooling Fan
Radiator Fan is a nine bladed fan measuring 400mm in diameter, driven by a 350 watt motor controlled by the EMS2000.

Low speed is switched on at 105°C (221° F) coolant temp and off when the temperature drops to 101°C (214° F).

High speed is switched on at 112° C (234° F) and remains on until the system coolant temperature drops by 4° C (7.2° F) at which point the system will revert to Low Speed.

The cooling fan will also operate on Low Speed when the Air Conditioning is switched on and system pressure reaches 8 bar (116 psi). Should the Air Conditioning system pressure rise to 18 bar (261 psi), the fan will automatically run on the High Speed.

02-03s have the 2plug harness w/ relay in fan assembly. The PS fan in these models turn on w/ highspeed, not w/ low. Post-03, PS fan turns on w/ low. Dealer can rewire your PS fan to turn on w/ LOW.

 

Was it the resistor or the wire that burnt? What wire gauge was used?

 

Thanks Minsanity for clearing the air and for steering me here. I just did some poking around after your suggestion in the other thread and found the PS fan stuck...again (how could I have forgotten?). I fixed that and let the car idle to make sure the PoS fan was working. That's when I noticed there was no low speed action, just high speed on the radiator. Looks like it's gonna take more than the coolant cap after all.

 

No problem, sir!

 

As far as mounting goes I bolted it to an 1/8" thick aluminum plate in the stock location. I cut up the plastic a bit in the area to increase air flow. I'm sure that helped with it's demise. I really didn't want the resistor out in the open and thought I could pull it off. The funny thing is it made it through our blazing hot summer no problem. Outside temp was maybe around 70 when it let it go.

I can't see the resistor at all where it is mounted but pretty sure it was the resistor that went. It didn't smell like burning plastic if the wire had gone. It was that very specific electronic burnt smell.

Also I don't think the fan temps that were listed above are correct. Going by the readout on my ultragauge low speed for me comes on at 203f and high speed around 220f. Mine is a mid year 03.

 

Hmmm, my scangauge confirms those temps when fans are called.
Banzai, should you go the resistor bypass route, it's best to oversize your wires. They won't heat up much w/o the resistor though.

 

Tinkered with the car this evening and found out why the resistor smoked. The main fan has gone bad. I jumpered the high & low speed fan relays together so it would run at high speed all the time. The fan didn't come on when I turned on the AC so I started poking around. After a minute or so smoke started to come out of the fan unit. Awesome. Wow has this car been an unreliable mess. I'm only at 65k and it's problem after problem.

 

Did the process in post #778 above.

 

I am currently reading this fabled resistor mod thread and I still can't figure out how to by-pass the resistor. I just confirmed today that my low speed is gone. I don't have a scan gauge yet so what I did was access the actual coolant temp through the ecu feature in the gauge. When coolant temp reached 221f(105c), no fan at all. The moment it reached 234f(112c), the high speed fan kicked in and I watched the coolant temp go down. And yes, the high speed fan cycles every few seconds with the AC on. Checked the low speed fan fuse hoping it is the one at fault but it is still good.

So what I want to do is temporarily by-pass the resistor all together and run the high speed fan whenever the low speed fan is called, without buying a new resistor as I plan to order a new Oem fan and keep it in standby while I milk the life out of this fan. It is my daily driver and although I have my AC on all the time (I'm in the Philippines) which prevents the engine running too hot, I'm sure it is unhealthy.

I have a 2006 MCS. Can you please help me out? I have very basic electrical skills and I'm sure splicing a few wires would be fairly easy.

Any help is appreciated.

 

Basically, you can bridge a new resistor across the thinner red wire and the thicker red
wire in the harness and it will do the same as replacing the resistor in the housing,
but much easier.
Make sure the new resistor has adequate power rating (about 100W) and is mounted
where air can get to it, hopefully against metal as a heat sink.

You can also just run a wire bridging the two red wires instead, which will give you high
speed when either low or high speed is called for.

 

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