[1bimmer]

Hi all,

I'm planning on removing headrest with active head restraint, and thus disconnecting power on 530d. Is it enough to disconnect only main battery, or I need to also disconnect aux one? Or you think battery should not be disconnected at all for this one?

[Joe-BMW33]

Originally Posted by 1bimmer

Hi all,

I'm planning on removing headrest with active head restraint, and thus disconnecting power on 530d. Is it enough to disconnect only main battery, or I need to also disconnect aux one? Or you think battery should not be disconnected at all for this one?

Just the main battery in the trunk. I assume you’re just swapping in a new charge unit?

[1bimmer]

I need headrest for leather repair. So just to disconnect the main battery, no special things to do (waiting for car to go to sleep or similar?)

[Joe-BMW33]

Originally Posted by 1bimmer

I need headrest for leather repair. So just to disconnect the main battery, no special things to do (waiting for car to go to sleep or similar?)

When you pull the negative on the battery, the car will go to sleep. No need to wait. Honestly, I’m not even sure you need to pull the main battery, but it certainly can’t hurt to be safe. The aux battery is fine to leave connected.

[1bimmer]

Cool, it is nice that aux battery does not need to be disconnected. Thanks

[Qsilver7]

Originally Posted by 1bimmer

Hi all,

I'm planning on removing headrest with active head restraint, and thus disconnecting power on 530d. Is it enough to disconnect only main battery, or I need to also disconnect aux one? Or you think battery should not be disconnected at all for this one?

If you have the active head restraints...they contain a pyrotechnic component...so I would HIGHLY recommend disconnecting the negative battery cable for your main battery...and if you do have an aux battery, disconnect that lead, too. The car is NOT de-energized if you have an aux battery and disconnect the earth lead to the main 12v battery.

There was too much info to capture...so I just have a little bit of the info for removing the ACTIVE head restraints. If you don't have the active head restraints...then no, you don't need to disconnect the battery.

[1bimmer]

I will not be removing catridges or anything related to active restraint. Will only remove whole headrest and give it for painting. Will disconnect both batteries anyway. Is there any special sequence, or just remove negative lead from main battery and then from aux battery? Thanks

[Qsilver7]

Just remove negative leads from batteries and either tie them back or make sure they don't touch anything metal. Since there's a pyro charge that explodes in an accident that moves the headrest forward...its probably connected to the SRS system...which if the headrest is like the seat belts...they can create an airbag warning light if disconnected when the battery is powered. So make sure you don't reconnect the battery until the headrest is plugged back in.

I usually wrap a rag around them or use my yard gloves if I'm working in the garage. When I was younger...I may have grabbed an old pair of stretched out athletic socks to protect the battery cable from shorting against metal. But they were the old long socks back then.

[Gazzaorty]

Hi expert,
Help needed !!!

I disconnected my car battery and turnk closed by mistake

What is ur advice to open it again

Car model is BMW 520 i 2018

Thanks in advance

[Qsilver7]

Originally Posted by Gazzaorty

Hi expert,
Help needed !!!

I disconnected my car battery and turnk closed by mistake

What is ur advice to open it again

Car model is BMW 520 i 2018

Thanks in advance

If you kept the BST intact and didn’t completely disconnect it from the positive battery cable in the trunk…you should still have power once you connect to the terminals in the engine bay. You can then use your remote or the interior trunk release button to open the trunk.