Battery Drain - Head Unit?

F

flipa10

New member
Hello all. 2007 Z4 with a bad battery. Changed it with robust aftermarket battery. The battery died after a few days. Dealer said it was blower resistor and changed it. Battery still dies. Started to investigate on my own. Found that the amp was always powered (it was always warm). Also found that head unit will play with no key in ignition, well after 20 minutes, even after opening doors. Removed fuses 47, 48, 50,and the 30 amp fuse in the amplifier in the trunk. Battery doesn't die anymore, but all I hear is the exhaust tune, which is not half bad, but no radio.

Is it the head unit? Or, is it the ignition? How can I rule out the ignition? It is a CPO, so no warranty coverage for radio.

Thanks all.
 
If you don't have sat Nav then the radio will work without key in ignition for 30 minutes our so.

is the amp OEM?
 
Hi and welcome to the Forum! Sorry to hear of your issue - hopefully someone will be able to help. Just a quick thought - if something is remining 'live' when you turn off the ignition you could try a meter across each fuse which will identify one which is live and isolate the problem.
 
Yes it is OEM. I replaced the head unit and the amp stays warm, even overnight.

AlanJ - a meter across over 50 fuses...ok! I can try.

Anyone know how to check for a faulty ignition switch??

Thanks!
 
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