Troubleshooting battery drain

[garfield81]

Hello members
This week all of a sudden my 2006 3.0 X5 alarm goes off suddenly in the garage. I run to the garage and see one headlight on and the other off and it slowly fading away and the alarm sound fading away as well. It seemed like the battery going dead and sure enough could not unlock the car with the remote.

Long story short the battery was less than 2 years old and got it tested and it came back good. Was told to test the alternator and tested at jump points I get 14.3V so alternator seems good.

Reading through the forums I have red the FSR being the drain culprit but I can't seem to find any symptoms of a bad FSR or I don't understand what the symptoms are with one of them being 'huffing'. Don't want to replace the FSR is its not bad.

Any help or further troubleshooting steps would be appreciated.

Thanks