How are you measuring the battery draw - multi meter between the negative battery cable and post?
DId you close the door to turn the dome light off, and then wait for half an hour or so? Some stuff doesn't shut down completely right away, and will throw the test off. If you've done all that, then the .4A is definitely too much. Start pulling fuses one-by-one, which should isolate the circuit that's causing the draw. Then, depending on which circuit is at fault, it may be easy, or not-so-easy (if lots of wires need to be chased) to determine exactly what the cause is.