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Hi All, Newbie here with a problem that 2 mobile mechanics have been unable to solve, I have a 2004 Mini One R53. About 4 weeks ago on the way back from work my Battery light started flashing on and off at approx 8 second intervals. By the time I got home, approx 3 miles later, it was flashing once every 2 seconds or so. First mechanic came, diagnosed Alternator problem and changed it. Next day after approx 5 minutes of driving the problem recurred, battery light flashes on goes off for 8 seconds,repeats with less time between flashes over next 3 - 4 miles. Mechanic swapped out Alternator for another replacement and next day same thing happened. I then took it to Halfords Auto Centre who had it for a day and reported it was an unspecified electrical fault that they could not take any further and it needed an Auto Electrician although they did confirm that the alternator was ok. I got an auto electrician up who has changed the serpent belt, tension arm and checked all pulleys are free and not binding., none of which has cured the problem. With an internal USB voltage meter I can see that when I first start driving the voltage is between 14.1 and 14.2 but after 5 minutes (or when the car is warmed up) the batt light comes on, Volts drop to 12.3 and go back to 14.1 when the lights go off. Voltage continues to drop, 12.1, 11.9, 11.7 etc until the car is parked. Next day same thing occurs, 5 minutes til problem kicks in and voltage slowly drops. I know this is a long first post But any help would be gratefully received as I am at my wits end. Please anyone out there...HELP!!
 

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This sounds a bit obvious - but is the battery 100% OK. When the battery starts getting slightly tired on these R53s, it can cause all sorts of bizarre symptoms and issues.
Out of paranoia, I also installed the USB voltage display (replaces the ciggy lighter one). Keep a regular eye on it.
 

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Hi, thanks for getting back. Yes, battery is ok and yesterday, to rule out the power steering pump as a possible cause, I disconnected it but the same problem occured. The one thing I did notice was that the cooling fan didnt come on at all while it was ticking over at the side of the road, and engine was running for a good 15 minutes. When the ignition was switched off, the high speed fan kicked in for about 5 minutes.
 

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i would disconnect the alternator big red wire run car with a voltage meter on it see what the voltage does, if stabilises to 14.1-14.7volts that would totally rule out or in the alternator,
so at this stage alternator is fine you battery is good after doing a drop test on it ie all of your mechanics should of done that test ,
knowing the issues with power steering pumps on those gen 1 mini's its very possible there is a intermittent fault with in the motor and its switching from high resistance to low resistance cause a massive dead short to the battery bit like put a jump lead across a battery in some cases have seen the battery explode from it,,
try disconnecting the power steering pump electrics see if fault goes way, also check if the fans all work these are another area where a high resistance could cause same sort of fault,,
you could rig a multimeter on amps wired between the positive battery terminal and the battery while car running see what the amps draw is, if it blows the fuse in meter then its very high and steering pump most likely,
 

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The one thing I did notice was that the cooling fan didnt come on at all while it was ticking over at the side of the road, and engine was running for a good 15 minutes. When the ignition was switched off, the high speed fan kicked in for about 5 minutes.
On my 2005 R53, 110k miles, the cooling, as in rad, stat, pump, seems to work really well. When driving, the high speed fan (HSF) rarely, if ever comes on. Only in really heavy, crawling traffic for a long time. In hot weather it occaisionally does the same as yours - when the ignition is switched off, the high speed fan kicks in for about 5 minutes.
I have an Ultragauge. Pic is sitting in crawling traffic for about 10 minutes in Tonbridge high street. Bottom left is engine temp - got to 107C. But no HSF cutting in. My HSF comes on at 110C. FYI, top left is intake pressure/boost and top right is intake temp, which is way up because there is no air flow through the intercooler.
However, if you want to see and watch the the actual temp on your car you can do this:
Display Actual Coolant Temp
R50 Cooper and R53 Cooper S Hatchbacks 2002-2006
R52 Cooper and Cooper S Convertibles 2005-2008
1. With the key in the ignition, but in the off position, press and hold down the odometer reset button with one hand.
2. While holding the button down, switch the key in the ignition to position 1 (first click) with the other hand. The screen will have a number and the word “TEST”.
3. Scroll through the numbers by pressing the odometer rest button, through to 19 and wait a moment. (Note: the number order is: 1, 2, 10, 19)
4. The message will say 19 "L i-off", flash to "L i-on", and back to "L i-off" again. When "log i-off" appears, press the odometer rest button again.
5. You are now in the system.
6. Scroll through to 7.0 Actual coolant temp.
7. Start the engine and actual temp is displayed and you will see the temp fluctuation as the thermostat opens and closes.
 

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Discussion Starter #6
Thanks for replying. I am leaning towards the Low speed fan resistor being blown hence the fan not working and the reason the battery light comes on and voltage drops once the car has been running for a while. I have disconnected the power steering pump electrics and the fault still occurs so I think I have ruled that out as being the cause.
 

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Thanks for replying. I am leaning towards the Low speed fan resistor being blown hence the fan not working and the reason the battery light comes on and voltage drops once the car has been running for a while. I have disconnected the power steering pump electrics and the fault still occurs so I think I have ruled that out as being the cause.
have you got jump leads,, if so just put the neg black lead from the neg side of battery to a clean metal point on engine see if still got the fault if fault still there engine earth main strap is fine , but if do this and fault goes away then chances are the wire harness inside its self has become intermittent high low resistance maybe..
also would run a voltage direct to fan motors seel if spin ok and not a dead short, a motor when first starting up for a split second is a dead short and as spins up becomes less,, if brushes or armature are worn out broken its possible to have a dead short every time the brushes hit the melted segment of armature as its all runs on electromagnetism (see i do know big words really lol) as a starter motor say and alternator work opposite effects but share some principles of function as such. so its possible for anything with a motor to have this effect as is the alternator with added effects from a control wire from ecu to switch it on and off,, ie the alternator has two small wires as well as the big red feed wire on modern cars, also it has a free wheel clutch on the pulleys as well.
just though would explain some depth in it as such, so you may find fan resister has failed but a by product of a over loading fan motor with a intermittent fault, so would pay to after fitting parts check the amps out put on the circuit for the motor to resister pack otherwise you could be replacing a second one and a fan at same time later, or mybe just as cheap to buy known good fan and resister as one unit to be on safe side,
 

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Hi all I am having this same problem with my r50 just wondering if anyone resolve this problem thank you
 
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