Battery drain on 335 when boot opened

Thaves

Member
Hi Guys

Need your expert advice, my 2010 e92 335i msport dct battery is drained flat when opening the boot even for a short period. I have had the battery tested and it is in perfect health, the car starts after being left standing for over 24 hours but if the boot is opened the ignition lights dont come on. I have removed the boot light but it hasn't fixed the issue. Some guy advised that it could be the boot switch which is faulty can anyone confirm this and where could I get one and how much it costs, plus how would I go about changing it. even a good auto electrician in the south of Johannesburg that I could use to diagnose the problem would be much appreciated.

thank you guys in advance
 

Thaves

Member
akash said:
Thats strange bro

Yeah it is as i cant seem to find any information anywhere on this specific issue


DannyBoyOPC said:
If u suspect the boot lock then i would disconnect it and test before buying a new one

thanks for the response, how would i go about doing that on the fuse box or directly on the lock?
 

Danny2

///Member
Thaves said:
akash said:
Thats strange bro

Yeah it is as i cant seem to find any information anywhere on this specific issue


DannyBoyOPC said:
If u suspect the boot lock then i would disconnect it and test before buying a new one

thanks for the response, how would i go about doing that on the fuse box or directly on the lock?



If you find a fuse for it then pull the fuse. I have never removed one from a BMW but mu guess is under the carpet on the boot lid is where you will find the motor
 

Thaves

Member
Thanks Guys
so had the battery tested and it was showing fine, went to BMW and they said i need to book it in for them to check, but they did say i should check all the earths, so Friday I stripped the entire boot to look for all the earths, checked all and they they were fine but still cleaned them. used a vault meter and noticed there was a drain but then the battery would pick up charge on its own. took the battery out and it charged fully in 20mins on slow charge. so my mech said lets try a spare battery he had and viola no more battery drain, voltage stays the same when the boot is open, so all along the battery was an issue, replaced and now happy.

DannyBoyOPC said:
Thaves said:
akash said:
Thats strange bro

Yeah it is as i cant seem to find any information anywhere on this specific issue


DannyBoyOPC said:
If u suspect the boot lock then i would disconnect it and test before buying a new one

thanks for the response, how would i go about doing that on the fuse box or directly on the lock?



If you find a fuse for it then pull the fuse. I have never removed one from a BMW but mu guess is under the carpet on the boot lid is where you will find the motor

 
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