2005 5.4L battery drains over night. Not noticable in summer only winter. I get the cold makes it worse. Is this a known issue with the alternator or do I need to check all the electrical components. Battery is 1 year old. I've had 2 batteries in the last 3 years.

 

Either start pulling fuses or use a digital multimeter to check for mA power consumption.

I just helped a friend do this on their 08 Focus. Pin pointed it to a piece of hardware using a meter.

Using a meter will give you instant results, versus the pulling and waiting game.

Do keep in mind, there are some you may need to "wait" 20-30 minutes for the module to go in to a sleep mode. So don't go crazy digging into something until you wait and watch the readings.

 

That would be for the instrument cluster on an 05. The timeout interval is 40 minutes.

If you want to simply check for an alternator draw, there's no need to wait.

 

Have you checked the condition of the Fuel Control Module located under the bed in front of the spare tire. Mine was corroded and broken open. Aluminum and steel touching is a bad thing. Once I changed the module the draw stopped.