E series? Good "always on fuse"

[kneecaps]

Wiring up a dashcam, and have a power saving switch box thing...needs a constant 12V supply. Thoughts on the 'least critical' always on fuse in E series? Don't want to piggy back of the CAS or something like that in case I blow a fuse somehow and then can't get in the car

[MarcoZandrini]

Do you have a fuse panel diagram? BMW typically divides up the fuse panel(s) into switched and constant sections. The switched section gets power only when the ignition switch is not in the off position. Constant section supplies power at all times. Check the diagram for a function that has to operate at all times. An option is the remote door lock/unlock feature.

[kneecaps]

Do you have a fuse panel diagram? BMW typically divides up the fuse panel(s) into switched and constant sections. The switched section gets power only when the ignition switch is not in the off position. Constant section supplies power at all times. Check the diagram for a function that has to operate at all times. An option is the remote door lock/unlock feature.

Thanks for the input, I can identify many "always on" fuses, but looking for a recommendation on something that is always on but is less critical. The door locking is controlled by the CAS module, and I don't want to put anything on that fuse on the slim chance my dashcam will blow that fuse etc. Since there doesn't seem to be any recommendations, I'll go over the diagrams and find something and report back with my final choice.

[MarcoZandrini]

Ahh, yes, the CAS module. Do you have a fuse chart? It seems BMW doesn’t want owners to have a clear understanding of what each fuse does, so it uses a cryptic fuse designation system. I’ve owned my 2018 M240i for almost 3 years and I still haven’t decoded all of the fuse labels. Why not go to www.newtis.info. It’s BMW’s official technical information system. It’s free. Enter the last 7 characters of the car’s vehicle identification number, hit enter and bookmark the page. Like the fuse markings it’s a little difficult to navigate but you should be able to identify a low priority always on circuit.

[kneecaps]

Ahh, yes, the CAS module. Do you have a fuse chart? It seems BMW doesn’t want owners to have a clear understanding of what each fuse does, so it uses a cryptic fuse designation system. I’ve owned my 2018 M240i for almost 3 years and I still haven’t decoded all of the fuse labels. Why not go to www.newtis.info. It’s BMW’s official technical information system. It’s free. Enter the last 7 characters of the car’s vehicle identification number, hit enter and bookmark the page. Like the fuse markings it’s a little difficult to navigate but you should be able to identify a low priority always on circuit.

Finding the fuses is not an issue, just picking a 'good one' is. I settled on an always on supply that feeds just the roof center console. This was on Fuse F62 on my vehicle. On E-Series, anything supplied via terminal KL.30 is "always on". For an ignition switched supply I selected the 'accessory/cigar lighter' sockets which were on F8 on mine.

If you want to find the ones for yours check out the '09 Vehicle electrical system / Front fuse and relay module ' diagram on your model, the fuses supplied by KL.30 (always on) and KL.15 (ignition switched) are there. Different terminals like KL.30g and the like turn themselves off after a certain amount of time...so don't use them unless that is what you want.