Help: Intermittent humming/buz car off - draining battery

[paolotvl]

2005 997 Carrera S with 74,000 miles. The other day while working in the garage I noticed a short, very low pitch humming sound coming from the car. It comes every thirty second and lasts about 1-2 seconds and sounds very similar to the noise the lock actuators make. I heard it a few times and thought "weird, I've never heard it before" but I didn't think anything of it. This morning, here in Houston finally we got lower temperatures, I go to start the car and the battery is dead. It had some juice, but not enough to crank. The battery was replaced roughly a year and a half ago and I drive the car about 50 miles daily. I thought it was the change in weather. I had no time to deal with it this morning so I took another car. Half an hour ago I went to recharge the battery and there was no juice left, completely dead. So I had to jump the fuse box to open the hood and jumped started it. I am now recharging it but the humming sound is back. It is not normal. I've had this car for four years and I would have noticed this sound before. Any ideas?? Thank you.

[AP 997S]

I suspect it's the front trunk control module.  It was a pretty common problem on early (i.e. 2005) 997's. My old 997 suffered the humming phenomena and it was correct by replacing the front hood control module. I could be wrong but the humming is a tell-tale sign.