[rejwan98]

Hi everyone, im in need of urgent assistance because i am absolutly clueless at what happened to my car today. I was driving on an incredibly busy roundabout and the car shut off entirely not a single light/ sign of power anywhere on the car, oddly the fans for the ac are still blowing even now after 3 hours.

my car was towed by RAC who tried using jump points on the front of car which was showing 12v, but yet no power absolutly anywhere on the car except the ac fan blowing. no access to battery also as boot is not opening either with jump leads or anything (i dont have rear folding seats), Tried bimmerlink and ista OBD port has no power

I literally cannot do anything or identify whats going on, just to mention a few symptons, no lights, no signs of power even windows door locks etc, speedometer/rev meter stuck on whatever it shutoff on, ac blower fan still blowing even after 3 hours after being towed.

any help will be much apprecated, Thanks in advance

[fe7565]

Originally Posted by rejwan98

Hi everyone, im in need of urgent assistance because i am absolutly clueless at what happened to my car today. I was driving on an incredibly busy roundabout and the car shut off entirely not a single light/ sign of power anywhere on the car, oddly the fans for the ac are still blowing even now after 3 hours.

my car was towed by RAC who tried using jump points on the front of car which was showing 12v, but yet no power absolutly anywhere on the car except the ac fan blowing. no access to battery also as boot is not opening either with jump leads or anything (i dont have rear folding seats), Tried bimmerlink and ista OBD port has no power

I literally cannot do anything or identify whats going on, just to mention a few symptons, no lights, no signs of power even windows door locks etc, speedometer/rev meter stuck on whatever it shutoff on, ac blower fan still blowing even after 3 hours after being towed.

any help will be much apprecated, Thanks in advance

The first thing is to get access to the battery by opening the trunk. Try this (1:40mins mark)

This requires removing some bolts to allow for enough gap at the rear seats to reach in or use a pole with a hook (cane) to pull the release tab.

[rejwan98]

hi, Thanks will try that in about an hour or so, i understand that the cars in the UK may not have that latch manual release, assuming this is the case, is there another way to open the boot/trunk?

[fe7565]

Originally Posted by rejwan98

hi, Thanks will try that in about an hour or so, i understand that the cars in the UK may not have that latch manual release, assuming this is the case, is there another way to open the boot/trunk?

Hopefully, someone from Europe would know.

[Zheez]

Yeah we don't have that release handle on our cars for some reason.

I'd firstly take the rear seat back out so you can climb in to the boot and at least disconnect the battery then leave it for a bit and try hooking it up again. Not a fun task but I don't think there's any other way.

Remove the seat bench by pulling it up then it's 2x T45 or T50 bolts in the area around the middle seat belt if I remember rightly and then you can lift the back up with some messing around.

[zatelli]

Originally Posted by rejwan98

hi, Thanks will try that in about an hour or so, i understand that the cars in the UK may not have that latch manual release, assuming this is the case, is there another way to open the boot/trunk?

My car might have the same configuration as yours, since it doesn't come with the latch release handle. If everything else fails, and you're unable to power up the car to pop up the trunk, your only option would be unbolt and remove the rear seats, which takes at most 10 mn. From that point on, you have access to the battery compartment.

Don't be tempted to jumpstart the car from anywhere but the front charging posts, or you might cause unnecessary damage.

I'm surprised you didn't manage to get the car to power up by connecting to the front charging posts. I managed to do it with 100% success rate with a 20A trickle charger. Make sure the clips are seated properly. If you're trying to jumpstart using another car, make sure to use larger gauge wires.

[rejwan98]

hi, thanks for the replies, its seems as though although im trying to access the battery the battery still has 12.4 volts, i check on front posts with a multimeter aswell as the tracker connected directly to my battery which also states on the app that the battery has 12.3 volts, so all of that said it seems as though the battery has power but its not reaching anywhere else on the car. Not a single sign of power from anywhere car was left with front windows down overnight, i tried connecting a noco battery booster to the front jump points with no response no power, and still unable to open boot/trunk. i will try opening back seat and access the battery, anyone have any suggestions what to look out for if the battery seems in good state or what to try

Once again appreciate your help

[rejwan98]

also would like to add that my car was retrofitted with angel eyes headlights close to 5months ago, i called up someone who essentially said that to try discconecting the headlights as try again i was told that this can happen and make the car go entirely powerless due to a short or similar, anyone have any clue? was also told it may also have something to do with the FEM module, what makes this esepcially hard is lack of access to battery and no diagnostics avaliable to me

[zatelli]

Now that you state it, you should look out for retrofitted parts, or anything that could be shorting out, yet it should have blown a fuse. As you also mentioned, the lack of access to diagnostics makes it significantly complicated to figure out what went wrong.

At this point, a portable charger, does not provide enough peak current to jumpstart the car. You'll want to disconnect the battery and charge it directly.

I'm starting to suspect that something connected to terminals 30 / 30B, is either causing a short or malfunctioning. BTW, did you have your alternator checked?

Also, by any chance, is anything plugged into your OBD port?

[rejwan98]

So, im trying to remove the seats so i could access the battery, Im assuming the altenator cannot be checked now due to engine not being able to start. nothing plug into OBD port (i did try connecting with ISTA via ENET cable which shows no lights or response) so although i was not able to access the battery i did come accross a battery charger which i connected to the front terminals, weird thing is now there is zero lights nothing on dash, no windows, doors trunk unlocking BUT my AC blower fan is running through the front vents?!?!, incredibly weird.

[rejwan98]

Soo managed to remove seat and access battery Not sure how i got in there as a 6”3 guy but see nothing and measured the battery which is registering 12.39v Kept bith posts disconnected and keeping a trickle charger on to see if it helps😭

[Billfitz]

If the battery registers 12.39v it's not the problem. You need to make sure there's power to all of the various fuse boxes, and take a look at the ground strap too.

[fe7565]

I would check the angel eyes circuit first, although I do not know anything about that short circuit issue with it. Do not want to dump more amps into a potential short circuit.

Then check the other fuses.

If you want to peace of mind and to help you focus in on the problem, may want to hook up a generic diagnostic reader. They are about $20 in the US (do not know in Europe), or can borrow one from one of the retail auto-parts chains (again, do not know in Europe).

Or get Bimmercode or similar app...(requires an OBD ELM Bluetooth module, $3 on Ebay).

The best longer term diagnostics for the bucks if you download ISTA+ (BMW's own shop software) and use a $10 ENET cable. This would be especially advisable, if you keep retrofitting parts in your car.

[rejwan98]

Originally Posted by fe7565

I would check the angel eyes circuit first, although I do not know anything about that short circuit issue with it. Do not want to dump more amps into a potential short circuit.

Then check the other fuses.

If you want to peace of mind and to help you focus in on the problem, may want to hook up a generic diagnostic reader. They are about $20 in the US (do not know in Europe), or can borrow one from one of the retail auto-parts chains (again, do not know in Europe).

Or get Bimmercode or similar app...(requires an OBD ELM Bluetooth module, $3 on Ebay).

The best longer term diagnostics for the bucks if you download ISTA+ (BMW's own shop software) and use a $10 ENET cable. This would be especially advisable, if you keep retrofitting parts in your car.

Thanks for the reply, Just trying to sleep on it, as im flabbergasted not knowing what is cuasing the issue, as far as im aware the fuse box located at the back is recieving and outputting power, my focus will turn towards the FEM module as others have suggested which i believe to be in the front passenger footwell, I dont have access to the OBD port since no power is being supplied to it ( wouldve been amazing if ista was able to connect)

[rejwan98]

Originally Posted by Billfitz

If the battery registers 12.39v it's not the problem. You need to make sure there's power to all of the various fuse boxes, and take a look at the ground strap too.

Been going through as many fuses as possible, incredibly hard due to the limited access through the backseats of the car, still trying to identify what is causing it

[fe7565]

The silver lining in this is, that if your OBD has no power, then it is very likely a fuse(s). If it's a fuse, then let's hope it saved the ECU modules too. Once you checked the major fuses, I would check the fuse supplying power to the OBD and go back from there. If you get the OBD up and running, that would help tremendously.

Check for short if you find the blown fuse. Without power, check both sides of the empty fuse holder resistance to a confirmed ground.


I would for now disconnect the angel eyes circuit. It will throw errors later, but at least you know what caused it. Let's hope the fuses did their job and protected the car, as they were designed to do.

[Billfitz]

If there's no power to the OBD I'm guessing a fuse in the front kick panel box.

[fe7565]

Here is the wiring for the OBD connector and FEM module. The FEM module gets power from two fuses. F504 is a non-replaceable 125 Amps fuse and is located in the rear fuse box Z3 in the battery compartment, not the trunk bottom.

F57 fuse is 40 Amps and is located in the front power distribution box Z7.


F12 is the 7.5 Amps fuse from the FEM to the OBD, but it will not work if one or both of the other two fuses are blown. Let's hope it's fuse F57. Disconnect the angel eyes, before replacing fuse F51, and /or check for a short to ground, which can mean anything between zero ohms and a few kOhms, and potentially even megaOhms.

[rejwan98]

Hi Guys appreciate everyones help, after so much fiddling and messing around i have identified the issue, it looks like the fuse box on the rear conncted to the battery has the input ended melted away seems like a short was causing this since it was not secured properly. i have attempted a temporary repair with the cable and looks like everything is fine, just awaiting to order a new fuse box and cable

Once again i appreciate everyones help and hopefully if anyone ever has this issue (hopefully not) they may be able to identify easier, I find it outrageous that BMW never thought of a backup to opening the boot/trunk when theres no power, this could have been so much easier if there was a manual way of opening it whether it be a latch or a key release

[Zheez]

Excellent, glad you have it sorted and found out why it happened. Lucky that it failed in the way that it did as that could've been a lot worse. Hope replacement bits didn't cost too much.

[fe7565]

Great to hear it’s solved! And without costing an arm and a leg.