While parked with the A/C on the car sounds like there is a blender or maybe a vacuum cleaner under the bonnet cycling on and off...

 

Were people using 12 or 14 gauge wire for this? I am thinking I will go with 12.

 

I can't remember the exact gauge of the wire that I used at the moment. I do remember that I used wire that was of equal gauge to the factory hi-speed side of the factory wiring. I would recommend using at least that size when you wire up your own resistor.

 

I went with 12 gauge.

 

Paranoia coupled with lack of knowledge is not a good combo when it came to this project. I thought that my low speed fan was not working, but it was simply because I didn't know the difference between the high or low. I wired the resistor in, operation was the same as before. I disconnected the low speed wire, no low speed fan coming on with A/C (obviously).

Then I took it back to basics. I put the wiring back to stock. I turned on the car without A/C. No fans. I turned on A/C. A fan cycles on and off every few minutes shortly after the A/C was turned on. I put my finger over the Fan 1 Relay in the engine bay, and it was clicking on and off with the fan. So, what I thought was the high speed fan, was actually the low speed. Also, it is important to note that it is around freezing right now, not warm at all outside.

 

I am glad to hear that yours is somewhat loud too. After determining that the fan did not come on until very high coolant temps were reached and well after A/C was on, I checked the resistance on the fan connector low speed wire to ground and it indicated open, i.e. resistor had failed. I added the new resistor and the fan behaves as yours does in low speed operation. Mine is also an early 2006 (built Oct 2005) so perhaps ours behaves a bit differently from some of the earlier fans. I triple checked connections, voltages, and relays to verify it was indeed the low speed fan setting that was kind of loud and also cycled. I wasn't completely sure at first because I only heard the high speed fan back in October when I first tested to see if low speed had failed and it was tough to remember how it sounded.

So perhaps the takeaway is that if you have a 2005/2006 your fan might be working at low speed even if it is a little loud and may cycle on and off, which is different from the general discussion here. Feeling the correct relay click corresponding to low speed fan operation sealed the deal for me.

 

Mine was built in 02/2005. The low speed definitely cycles on and off. Maybe when it's hotter outside it will stay on longer.

There is a local MINI meet today where I am located and I am going to be inspecting the fans of other R53s.

 

I have now read through the 18 pages of this topic, and from what I gather:
the low-speed radiator fan comes/is/should be on all the time while the A/C is turned on and functioning correctly, no matter the ambient temperature: A/C on should = low fan on (at least);
the power steering fan will not come on if the low-speed fan does not come on first;
not sure if the power steering fan is scheduled to come on with the high-speed fan but I assume it should;
the low-speed fan is pretty quiet, while the high-speed sounds like a blender and is intermittent, depending on coolant temp.

My '06 R53 does not run hot at the moment; stable mid-range needle on the temp gauge. My fan symptoms are indicative of the burnt resistor. That is, I have no low-speed fan with the A/C on, and my high-speed fan turns on and off. Both/either relay in the fuse box works in the high-speed relay slot, while neither works in the low-speed slot (a good way to check for bad relays). At idle, my A/C seems like it could use a refrigerant charge - but, this symptom may be due to the low-speed fan not doing its job at idle or low vehicle speeds (in traffic).

Further, I believe that the high-speed circuit should kick in only rarely; on real hot days, when stuck in traffic, etc. The fact that any of us is hearing our high-speed fan kicking on and off frequently should be a red flag this time of year.

Diagnosis: my high-speed fan is doing the work that the low-speed isn't. This may not kill my engine, but it may kill (or has killed) my power steering pump, and may kill the fan itself prematurely. Not sure how easy my steering wheel should turn, but it's significantly tighter than my Z4 (also electric power steering). I'll have to do the resistor repair, maybe even the full fan R&R. Then I'll see if my power steering pump and fan are functioning properly.

Update/edit: after replacing my entire fan assembly, the low speed radiator fan does come on with the A/C. However, my power steering fan did not come on. I removed the P/S fan and hotwired it - and it does work! I'll have to do more research as to when the P/S fan is supposed to come on. It would make sense that it only comes on with the high-speed radiator fan circuit.

 

Good synopsis filmy, though you should also note that the lack of low speed fan may also kill the A/C.

 

I found some scrap aluminum and bent something up. The resistors are 0.68 ohm/50W. They don't boil water but they get HOT! Dissipation is right at 50 Watts. I'm not sure I am happy with this yet - need more sq inches I expect.



Solder/spliced wires here on the fan side. Liquid electrical tape is drying, then I'll tape it up. There are insulated female quick disconnects on the ends of the 14 gauge drops.

 

I'm so happy to have found this thread. I've recently had trouble with the power steering on my '02 R50 Mini. No dealerships in my state and the local BMW-certified mechanic was booked weeks out. So . . . I took a chance and bought a new (not refurb'd) power steering pump and PS cooling fan from SteeringPumps.com. Replacement of the pump/fan wasn't physically easy, but it wasn't terribly difficult either. Steering has definitely improved, but the new cooling fan has yet to kick in. I've taken the car for long drives, left the engine running and cranked the AC all in the hope of forcing the fan to spin. I then take my shop light and get as far under the front bumper as I physically can looking to see the cooling fan blades spinning . . . nothing, even as the radiator cooling fan whirs wildly and cycles repeatedly. I have yet to bench test my new PS cooling fan, but from all I've read here, I'm nearly sure that my low speed fan function is kaput and I'm ready to blame the resistor. Others in this thread have helpfully pointed to RockAuto.com for parts, but I'm confused. Should I be looking for the pre-assembled fan/shroud for sale or is a bare resistor available? My British version of the Haynes manual suggests that the resistor is a replacement item and that it can simply be re-soldered into place, but others writing here seem to indicate that we're talking welds, not solder points. Even if I were to get the pre-assembled fan unit from RockAuto, the most expensive option I've seen is priced around $108 as opposed to the roughly $325 that ECSTuning would ask for what looks like the exact same part. Any suggestions or recommendations would be greatly appreciated.

Also, I took lots of pictures, some blurry, with my iPhone as I replaced the pump and cooling fan and want to post these with descriptive text (as a small pay-back to the many people on that thread that have offered so much helpful advice) at the end of the power steering pump "sticky," but I'm new to this and could absolutely do with any guidance regarding embedding JPEGs in a text reply. Many thanks in advance.

 

I decided to do something about mine today. Since the external resistor is not available from Mouser at the moment, I sourced the Tyco brand noted in an earlier post from last September. It's less than $10 from newark dott com (P/N HSC100R47J). As noted in that earlier post, it's a 0.47 ohm rating (not 0.33) and will spin the fan a bit slower - just how much slower, I don't know - in low speed. I've PM'd that poster about his outcome but haven't heard back from him yet. I'll probably get one to have around in case my other option (below) doesn't work out.

I saw at least one resistor seller on ebay who would make a 100W resistor in a custom ohm rating, I assume the 0.33 is doable since their advertised power resistor was exactly the same build config as the Mouser one. Looked like his higher priced resistors were in the $50 range.

Other option is a complete new fan assembly, which I found on the 'bay and ordered for $79.06, shipped. Search item #170628148617. I'm sure it's the same quality as what others are selling in the same price range - I seriously doubt it's a Dorman unit, as that brand is being sold in the $150 range. I should have it in a few days. If the fan grenades in a short while, it has a lifetime warranty (as far as that goes). Like all of us, I'll have to keep my eye on it.

(A note on the cheaper fans: I figure that the fan motor on these Asian assemblies is the weak point of the entire assy. When I remove my old fan housing I intend to keep the fan motor assembly, if I can remove it, for reuse if the new fan grenades.)

Once my low-speed function is working again, I hope to find that my P/S fan also comes back from hibernation. I wasn't able to discern if that fan kicks on with the high-speed radiator fan or not. IOW, I doubt the P/S fan has been working at all in my new (to me) Mini S.

 

Dear Filmy,

I like the idea of "refitting" the non-OEM housing with the stock fan. It seems all we're really after is the resistor, but that's the most difficult part to secure and to be sure of. I don't have any doubts about the integrity of my radiator fan's motor, so I think I'll borrow your terrific suggestion. I'm still a little torn, though. Should I spend the relatively small (given what I've already dropped on the pump/fan) extra amount on the Sherman vs. the Dorman and STILL do the fan swap, or just get the slightly more expensive Sherman, swap out the whole assembly and hope that everything begins behaving as expected? I dunno. I'll certainly set aside the old housing, when I do finalize my plan and finish the replacement, just in case I might need "spare parts." Do you know if it's absolutely required to drain the radiator and remove it to replace the cooling fan? My Haynes manual maintains that it is, but for obvious reasons I'd like to avoid that messy job if at all possible.

I almost forgot to mention, your Mini S is awesome. Love the wheels. While my R50 Base is Chili Red, before I'd found it I had my heart set on the pearlescent silver. Beautiful. O.K., forgive the flattery, but yours is a very sleek-lookin' car.

 

My decision was basically, as a Mini owner I should know how to get my car into "Service Mode" so it would be a learning experience for me. It's not too difficult from what I understand, so I don't mind installing the entire assembly. If I were you, having already spent the big bucks on a new P/S pump and fan, I'd use the best parts available to support that money I'd already spent. You're talking about a $50 or so difference, I think. Cheap insurance.

AFAIK, draining coolant is only because you have to disconnect the upper radiator hose to lean the rad out of the way, and coolant would, of course, pour out of that opening. I'm thinking that I don't really have to drain much coolant - just enough so that there's only air in the top of the radiator - maybe a gallon or so.

Thanks for the compliments. The PO spent the extra money on factory wheels - too bad she wasn't more careful around curbs. But yeah, the overall appearance of the solid gray with the nice wheels was what sold me on it. I like the Chili Red version, but I've already had a red car ('95 BMW 540i/6) and I like rolling a bit more "under the RADAR" these days.

 

The radiator definitely does NOT need to be drained. Just pull the top hose off the radiator and tie/bungee it to the bonnet. You'll lose a little bit of water, but much less than draining the whole thing. That will give you room to move the rad forward to access the fan assembly.

 

Thanks again Filmy--and now Eric--for the tip regarding the radiator. I have yet to bench test the new PS cooling fan, but that's next on the agenda. If it works properly, and I expect that it will, I'll be ordering the best aftermarket radiator fan assembly I can find (in the $150 area as opposed to the $300+ dealership price) to see if I can't get this low speed fan/PS pump issue behind me. I'll definitely take pictures as I make the repair and follow up with results on this thread.

 

Here's the promised follow-up:

Try as I might to bench test my new PS pump cooling fan, I couldn't find any way to get it spinning. I tried rigging short test leads and running them from the pins inside the fan's snap connect to the terminals on my battery, but only for a fraction of a second out of fear of doing more harm than good. I never saw even the slightest movement of the fan blades. So, this raises the question of whether there is some sort of thermal sensor built into the SPAL fan. What's that black rectangular housing just back of the plug?

I called SteeringPumps.com and described my dilemma to a very helpful tech/sales person. He suggested that I put the fan back, turn on the car, crank the AC and put my voltmeter on the wiring harness that leads to the radiator cooling fan. I did just that. I noted some interesting things. When the AC was on full and the engine was idling, but very warm, I tested for about 14 volts between each of the hot pins and the brown "earth" pin. The radiator fan hadn't started spinning right away when I turned on the AC, but by the end of my experiment it had stopped short-cycling and was spinning non-stop. I turned off the AC, disconnected the 3-wire plug and put the meter on it again. This time, only one of the two striped wires was hot. I reconnected the plug, but the fan did not come on. Here's my guess: the current I was reading was intended to power the low speed fan, especially as my engine was now hot and the car wasn't moving so the radiator wasn't even getting "passive" cooling. This whole venture has been a confidence-killing experience and I'm still not sure I've isolated the problem. I do know a couple of things. In all this, I have yet to see the blades of my PS pump cooling fan spin. The pump itself, which was pretty quiet at the beginning of this latest test, was whining softly but steadily, even when under no load, just before I turned the car off. I'm just about ready to order the radiator fan housing assembly from SteeringPumps.com ($164) and hope that all this irritating weirdness is down to a faulty resistor in the fan. Given that I can't afford to keep throwing money and parts at this problem, though, I'm always interested in any suggestion anyone might have.

I took a picture of the connector I've been testing with my voltmeter. Does anyone know what the smaller 2-wire plug runs to? My Haynes manual is no help, but I'm guessing that it's connected to the coolant temperature sensor?

 

Those two wires activate the high-speed relay inside the fan assembly.

There are three schematics on the bmw-planet web site that show engine cooling fan (ECF) and power steering fan (PSF) wiring. Up to 3/2003 there are five wires for the ECF. The three-wire connector is X53 and the two-wire is X5301. If the wire colors in X5301 are BN (brown) and GN/RT (green/red?) then you have the earlier version valid up to 12/2002. The one after that is valid up to 3/2003 and the wire colors in X5301 are GN/RT and BN/GN, which are green/red and brown/green if I'm deciphering these things correctly.

• Up to 12/2002 the PSF will run only when the ECF high-speed relay is activated.
• After 12/2002 the PSF will run when the ECF low-speed relay is activated.

After 12/2002 things get interesting with respect to the PSF operation and the dropping resistor.

One would think that Mini engineering would want the PSF to be powered whenever the ECF was powered, at either low or high speed. One way they could do this would be to sequence the ECF high- and low-speed relays so that with the ECF at high speed both relays are activated. Since the PSF is powered when the low-speed relay is activated this would ensure that it would also be powered when the ECF was at high speed.

If on the other hand the low-speed relay were turned off when the high-speed relay was on, the PSF would still run because it would be back powered through the dropping resistor. If this was intentional design and if the dropping resistor were damaged you would have the odd situation where the PSF would run when the ECF low-speed relay was activated (but not the ECF itself) and not run when the ECF was at high speed.

Angrydad, if you have the early Mini the PSF should run whenever ECF is at high speed. This should happen whenever the green/red wire in X5301 has power. If you never see that wire active then you have no ECF high speed and no PSF.

It looks like a pretty easy mod to convert the early Mini PSF wiring to the later style.

 

DIY'd the fan assembly today. Piece of cake! The part was only ~$80 (shipped). Total R&R time: 1 hour. I used this walk thru: https://www.northamericanmotoring.co...ml#post3273478

I did not empty any coolant from the bottom hose. I lost maybe a pint of coolant (total) when I pulled off the upper hose (and tied it up to the bonnet). Not only is my coolant green (not correct) but I'll get the dealer to flush/bleed the system this week, so I'm not worried about low coolant at the moment.

I also kept the fan motor/blades from my old unit. Since the resistor was the problem, no reason to pitch a perfectly good fan - plus, it looks like it will fit perfectly in the newer housing should I have to use it. I had to cut the wires near the resistor, but the motor just unscrewed from the housing.

Oh... and it WORKS NOW! Low fan speed comes on with A/C. Don't know about the P/S fan, but I'll have the dealer make sure when they flush it.

 

does your low speed fan cycle or just stay on?

 

It stays on - as long as the A/C is running. I haven't turned off the A/C yet, but I would think that it cycles when the A/C is off and the temp gets to whatever is supposed to kick it on. Running down the freeway with the A/C off, I would think = no fan.

 

Filmy,

Good to hear the encouraging news re: your new fan housing. I've already got the Dorman unit from RockAuto.com on order and look forward to making this repair myself. The link you provided will be a great help. Bradley99 has thoughtfully sent along an analysis of the wiring schematics for pre-02/2002 Minis and there's a possibility that I'm not supposed to see the PS cooling fan spinning until the high-speed ECF is operating as there's a two-wire group that's supposed to power the high-speed relay inside the fan and somehow (I don't pretend to understand the Mini's wiring) feed back to the PS cooling fan. If that's true, I may have bigger problems than a degraded resistor in the fan housing, but I'm going to trust to luck and start by replacing that very part first. I'm really glad to hear that you've got your low speed fan back and will be interested to see whether or not you've got the PS fan functioning properly. As to the proper color of the coolant, do you know what I should be looking for when I do the partial drain of my radiator?

 

Blue. The BMW-spec coolant. But I don't know if that's them putting their own "Marque" on it. In a coolant search, I noted that someone suggested that there's an aftermarket equivalent but didn't say what color it was. Of course, it's the chemical mix that's important, not the color. I just know that I have green propylene glycol in mine - not the spec.

Update on coolant color: after getting my coolant flushed at the Mini dealer, they told me that either green or blue is okay, and they can be mixed. However, do NOT use the red/orange color - it will all turn to gel if you do.

GL with yours. PM me if you have any questions, but I think you'll find it's a piece of cake. It's amazing that you can just pull off the front bumper and have the engine almost in your lap.

 

Ok just alittle confused. Read though thr whole thread and still have this question. I have an 06 MCS, fan turns on when AC is on BUT according to my scan gauge the fan under normal operating conditions turns on around the 220 degree mark. I was under the impression that the low speed fan kicks on around 198 degree mark.......so confused.

And is there still someoone putint together the relay fix for the fan?

Thanks

 

Confused? I can certainly identify with how you're feeling. My recent exchanges with Filmy and Bradley99 have been very helpful and I feel as though I'm approaching my problems with the PS pump, the PS cooling fan, and the engine cooling fan in the correct way, but I have yet to solve this puzzle. I was unaware of the temperature range specs at which the low- vs. high-speed radiator fan should come on. I'd thought that only the high-speed fan has been working on my '02 R50 base, but by Bradley99's description, the high-speed fan literally screams and I wouldn't describe my fan as sounding like that.

I did talk with a Mini dealership service technician and he told me that when I turn on my AC the low-speed fan should immediately come on (which definitely ISN'T happening). In the next breath, though, he said something to the effect that the '02s were "weird" when it comes to this whole low- high-speed ECF and PS cooling fan. That comment sapped whatever confidence I'd gained in my understanding and diagnostic abilities.

So, I may be looking at low-speed fan only. Anything but sure of what I'm doing, though, I have already ordered, and committed myself to installing, a new engine cooling fan housing--this just to replace what may be the faulty low-speed fan resistor. Having just finished the fan replacement, Filmy assures me the job is relatively easy and that low-speed fan function has returned.

On top of everything else, I think I may be facing yet another steering-related problem. I was driving my Mini over the weekend--and obsessing over the "feel" of the steering the whole time--and I found that steering was alternatively smooth and then stiff. When I had the car parked and idling, I could turn the wheel and hear the familiar motor whine of the PS pump. So, I believe I've got a working PS pump (whether or not the cooling fan is working properly) and that the intermittent feel of the steering may now be down to the lower steering column u-joint being compromised. I'm debating whether or not to surrender my car to a dealership for diagnosis or finding and ordering the steering column parts necessary to try the repair myself.

My theory, for what it's worth, is that somewhere along my car's past the PS cooling fan stopped working, either because of a fault with the low-speed fan resistor or because it had become so gritty and begrimed (when I dropped it, the blades would bind as I turned them and it looked beat). Without cooling of any kind, my PS pump began cutting out with the built-in thermal protection doing its job. Eventually, though, the pump had had enough. While the pump was on it's way out, it may have placed added stress on the u-joint at the bottom of the steering column. Given that these finely-tuned systems are all linked and that my Mini has over 95K miles on it, things have basically come down to wear and tear.

I'm sorry I can't be of more help, but if you find the answer to your question, I'd be very interested.