Easiest way (in place) is to see if it comes on at 221deg. if you have scanguage or similar.
I measured the resistance on my failed fan at 1.6ohms IIRC. I forgot to check the resistance on the replacement fan.

 

Only what i read on this thread, when you switch on the A/C the fan should come on low to cool the rad if it fails the A/C system can overheat and go wrong..again only what I read on here.

 

Just for the Mini, I've developed a crude habit of checking the fan operation. Once a couple of weeks, I turn on the A/C and check the fan to see if it's running on Lo-speed. Just put my ears in front of the radiator grill and I can hear if it's working.

Not sure it's a guarantee that a functional Lo-speed (with AC on) = functional Lo-speed activated by the thermo-switch. Does anyone know?

 

I don't think the low speed fan comes on immediately, mine does not, even after the resistor was in place. I think that I mistakenly thought that the low speed was the high speed and that if I installed the resistor, all would be right. Did not work for me. I spent money and time chasing this dream.

I am not saying that what you are experiencing is the same as what I ran into, but before you go down this road you might just get the air conditioner checked first. Maybe ask the shop if they can just check the compressor. Maybe take it to MINI to get it checked. It will cost a bit of coin but you will know what you are looking for. Might save some time.

 

I think it should be clear this thread is to fix the low speed fan resistor only, Not to fix anything to do with the air conditioning, do not do this fix unless you are sure the resistor is blown, as if you wire it as some people on here have done without disconnecting or cutting the low speed wire and it hasn't blown you will have two resistors in parallel to the fan and it will run at the wrong speed.

 

The high speed fan sounds like a helicopter taking off and is loud even inside the car with the radio on if you cant hear it in the car over the sound of the engine its on low, when the low speed fails and you have the AC on, the fast speed fan cycles on and off in loud roaring bursts its unmistakable.

 

See my earlier posts - the fan will only come on if the AC reaches 114psi - so if your r134a is low, or your compressor is bad (and possibly even if the engine is cold, I'm not sure how the AC pressure builds). I know this because my recently replaced fan triggered at 221 deg, but not with the AC on - until I filled it a bit. So fan/AC problem symptoms can be interdependent.

 

I have a new fan (Rock Auto) and charged system...and still no A/C. Can anyone offer a next step to fixing the A/C. I know this thread was for fixing the fan resistor, but I think the main goal of fixing the fan resistor was to repair the A/C.

 

I agree with what drozd said, in that this thread is about fixing the low speed fan. However, my A/C not working is what brought me to this thread in the first place.

I do not sit still long enough of the fan to kick on for temp.
Call me lucky, but I do not have a lot of stop and go traffic to sit in.

I did diagnose that the fan was not coming on after punching the A/C button, nor if I left it to sit and idle in the driveway. The fan only came on when the temp gauge (chrono-pack) was well over 200. Yes it was loud.

It is also my understanding that the A/C (compressor) is not supposed to run, unless the low speed fan turns on. Hence the delay in startup. Someone correct me if I'm wrong.

So, here I am, no low speed fan and no A/C.... waiting on my resistor to arrive.

 

What temp was it outside when you were waiting for the fan to trun on? How long did it take?

 

If you were referring to me, it was about 90F. Car had already been ran, so it was hot. No fan until, as mentioned earlier, the temp gauge read well over 200F. Then high, noisy fan.

Same goes for the A/C. In trying to not f up my A/C system (based on some suggestions [from various people, including MINI techs]) I only pushed the button to try and get the compressor to kick on. This was 30 seconds or less. Neither the fan, nor compressor did. The fan only came on when the temp got high enough.
Typically on my MINI, the A/C would come on within a second or two of the fan. To be honest I don't remember which did first when it was working normally.

On a side note, I did plug up a set of gauges - there is enough pressure on the lines to make the fan turn on (according to Eric). 118-ish (near 120)PSI when nothing is running. Equal on low and high sides.

Now, all I need is the time to wire in the resistor to see if I have any other things wrong.

 

thatatvguy. How long did it take your mini to get to the temp where the fan turned onwhen it was 90 out?

 

About a minute or two. Not long, but not instant either.

 

I think I may have accidentally developed a test for low speed fan operation.

I have an 03 MCS and I was working on the AC but found this thread.

I unplugged the AC low pressure switch(huge PITA) and the low speed fan came on about 3 seconds after I started the engine. cold engine. Soon as I plugged the switch back in the fan went off.

can anyone else confirm this?

 

Haven't tried that, but it sounds more like a test for the AC system than the low speed resistor.

 

while you might be right. it does trick the car into turning on the low speed of the fan. so with that you could know very quickly if you have a working low speed or not. even if your AC is totally dead and doesn't work.

 

Just got my resistor from Mouser, fast shipping, I ordered it Monday, got it Thursday, will be installing it this weekend. $26 with shipping to NJ.

 

This is a very helpful thread! I have a non S Jan 02 build. The low speed fan resistor burnt to a crisp. I assume this happened a few years ago as until recently the high speed fan would come on when temperature required, which was often (its very loud). With no low speed fan and warm climate in Austin the Fan Motor eventually died all together. The A/C system was damaged as a result, the compressor clutch finally failed (as per diagnostic).

I replaced the whole Fan assembly
Replaced A/C compressor (no point to swap without fixing fan first )

I am disappointed that the failed resistor and fan was neither diagnosed or fixed before the compressor could fail. (i just had the 100k stage 2 service 6 months ago by a independent shop locally) (austin just got a dealership)

I am not trying to spread fear here....
The point is that the low speed fan failure going undetected for a prolonged period (especially in the heat of summer) could cause some expensive damage... Fortunately, thanks to everyone's help here i was able to DIY the fix for a lot less than the $1400 mini dealer wanted....

Now on to the next DIY maintenance

 

Same here I always thought the fan only would come on to cool the engine at high temp, I did not know about the low speed fan untill I read this thread, I'm sure there are lots of minis about with the ticking timebomb of a blown resistor.

 

How do you test the compressor?

 

You will get a better response if you ask this in a new thread.

 

Update to my posts from May/June where I display photos of my resistor mount on the wiring bracket. Very happy with the fix. Now, I do not use A/C frequently (it is a convertible after all), but I did take a few highway trips and use the A/C, and thus use the low speed fan at length. No problems to report from this fix.

 

Guys,

So I recently purchased a Cooper S and I noticed the fast fans spinning up, having had this previously on a SEAT and VW I had a feeling thta the slow speed fans had failed - suprised its happened to another make to be honest, but anyway.

Luckily from reading this I can do a similar fix to the MINI as I did to the VW.

From what I can work out I need a resister and simply just wire this in. I have found the following (from the UK)
http://uk.farnell.com/jsp/search/pro...sp?sku=1174281

just really need to confirm which wires go where - I've read through this topic a few times and I'm getting a bit lost in it if I'm honest.

Its a 2004 car by the way.

 

I put my resistor here: Cut 14GA green/red, soldered/shrink wrap resistor, output to scotchlock on 12 GA blue/red...Brown is ground. covered in harness plastic to hide wires. clears hood latch.

 

So in noddy terms, cut the cut the wire and fit the resistor inline? Obviously you dont need to cut it you could disconnect etc but just trying to explain it in real simple terms.

I take it you can only wire the resistor one way round or does it not matter which end is which?

oh and thanks for the pic.