2007 Mazda 3 1.4 Petrol. I have a problem with the battery draining overnight. Battery load tested and alternator tested ok. Noticed that the interior lights were dimming but not going out when the doors were closed but battery continued draining with the interiors lights selected off. Tested all the door switches and all ok. I used a clamp meter to try and locate the drain and found the cable to the current sensor on the negative battery terminal was reading 0.35 amps with everything off. I disconnected the current sensor connector (3 pin) and now the interior lights go off properly.
Question - does anyone know what the current sensor does? Can I just leave it unplugged?
Thanks in advance

 

Further to the above, I retested the battery on an analyser and it showed a dead cell so put a new battery in. The ammeter is now showing a parasitic discharge with the ignition off of .89 to 1.25 amps. I have tried pulling the fuses one by one but don't seem to get any change. With the new battery in, the interior lights now go off when the doors are closed.

 

Along with all the fuses, you will need to unplug all the modules 1 by 1. PCM, SRS, BCM, ABS etc

 

Thanks for the advice. I will try tonight. To isolate the alternator, do I remove a module or disconnect the alternator connectors?