After sitting for 45 minutes my sister's 1998 323is would not start. After I checked it several hours later the battery showed 10V on my multimeter. Figuring it was just a drained battery, I tried to jump it with my other car. When trying to start the car I just get a loud CLICK then nothing. Also it acted a little funny after that. I disconnected the jumper cables, then reconnected and tried again. Same thing. I also noticed that when the key is in ignition position (I still get some power) relays K13 and K21 (i think those are the numbers, I got them off a website) were buzzing and clicking back and forth. ALSO, I'm getting a check engine light, but I dont know how to get the code.
I know cars well, but not BMWs. If anyone has any suggestions I'd be very grateful. Thank you.