Crazy temperature gauge, dash lights, driving lights, window behaviours...
I have this Mini 2004 which was working fine until last week. All of a sudden:
- a morning tried to start the car and starter wouldnt work, main headlights flashing randomly, ABS and flat dash light flashing, dash lighting system dimming randomly, driver window going up and down...Ticking noise in engine bay... etc, etc....
- Removed the key, ensure the light control was off and locked the doors: Then noticed the driving lights were on!! I managed to start the car and stop it, then the driving lights turned off...
I initially taught it was the alternator or the battery:
- I tested the battery voltage car off : 12.98V, Car on: 14V so I suppose the alternator is working and charging.
- I replaced the battery by a brand new one (I even fully charged it)
But same problem... But now as soon as I plug the battery the driving lights stays on and noise in engine bay goes on and off randomly... So I need to unplug my battery otherwise it would get drained...
I did some search in forums and a frequent problem seems to be the BC1 (body control unit), so I just removed it from the driver footwell and opened it to see if there was any water or corrosion in it. But seems all good: no water or visible corrosion...
Not sure what I should do now... Any suggestions???
You can't really test the BC1 unit yourself and a secondhand unit would need to be re-programed to your car. Companies like BBA-Reman can check and refurbish your own BC1 unit so avoiding programming/coding issues.
More here: The BC1 (Body Control Unit) - Forums
Are you sure all the body cavities under the floor carpet are dry as the thick soundproofing in them can often hold pints of water like a sponge, while carpet remains dry on top. The cables and connections/earth points running underneath the soundproofing felt along floor/sills can be wet causing similar problems to a damp BC1 as the various signals sent around the BUS wiring network to other modules get confused/short out.
Hi, no under-carpet seems dry and grounds connection at door sills seems non-corroded in perfect state.
Personally I no longer think its the BC1, see why below:
Today I started the car, removed the key from the ignition and the engine was still running!!! Had to unplug the battery to have the engine shut down...
A pump in the engine bay is also running randomly (event without the key in).
Scanner returned only 1 code P1913 (steering angle sensor...)
So here is a summary of the issues:
- Engine running even after removing key
- Car not starting - randomly (just hearing a tick-tick-tick)
- Pump in engine bay running randomly
- Driving light always on (even without key)
- Xenon light flashing when starting
- Dash indicator lights going on/off randomly (handbrake, abs, dsc/asc, checkengine, etc.)
- Dash lighting system dimming randomly
- Temperature gauge going up (reaching the max with Red ligh warning) to min.
- Engine rev going to idle to 0
When turning key off to shut down engine, is this a signal going to the ECU throug the CAN-BUS? or is this a relay direct to ECU? Is this issue telling us more info? I dont think the BC1 is connected to the Can-bus, but more the IKE no?
Is the pump in the engine bay that is running randomly the power steering pump? (even without the key in). It is down low behind the engine.......it has a 100A fuse so draws a lot of power and when its internal control circuits go faulty can also create random electrical issues around the car as the alternator cannot cope with the extra electrical demand/loads/shorting out from the faulty ps pump. More info here: Power Steering Pump replacement - Forums
I double checked and: my mistake, its not the steering pump. But I am almost sure now its the streering pump FAN (it makes the sound of a fan and its controlled by the fuse F39). Now I just retried and its no longer random, its stays ON as soon as I plug the battery (even without key in). I also tried with this Fuse F39 out and the noise was no longer their (fan was OFF) but my car strange behavior still present .
Latest behavior recap:
1. As soon as I plug the battery I have:
- Driving light on
- Some dash indicator steady on: Battery, Check-engine, EML.
- Power Steering pump FAN
2. If I enter the key in the barrel:
- No noticeable change to above
3. If I turn the key to start the engine:
-Engine start as expected
4. If I turn off the key and remove it from the barrel:
- Engine keeps running (no change to above. So I had to remove the main relay to stop the engine).
This means its like if the ONLY key position the car recognise is when I turn it to start the engine... Else, the car thinks the key is always in on "running engine". That is probably why I have driving lights always on, the steering pump fan on and the dash lights on..
Could it be a bad relay stick to ON position (for ignition barrel)? Should I check if the Main Relay is always energized (I think I understand the ignition barrel switch-on the Main Relay?)
During this last tried behavior things didnt seem random (i.e.: no randomly flashing dash indicators light).
ok, I found the electrical diagrams in the technical documentation package in one of your links, thanks!
Now, based on the diagrams, the fuse FL7(50A) and F12(20A) should be powered when Ignition is on RUN and START. If I have those fuse powered without key-in then I believe the Ignition Switch is defect. The ignition switch seems the only mecanism opening/closing those fuse circuits. I will check that tomorrow.
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