The battery suddenly went flat overnight and now all that happens is the hazard lights keep flashing, no power to starter, can hear the fuel pump going though. Sounds like the anti theft is not working properly. Car hasn't got remote central locking. Have charged battery but may not have charged enough yet. I found a black box under the glove box that had lots of wires going to it & when disconnected stopped the hazards from flashing all the time. Could feel & hear a relay going inside. When switching hazards on with switch another relay makes a horrible buzzing sound. Any help or ideas much appreciated.
The car is an e36 4 door 320i on a k plate.