Recently I have been experiencing a battery drain on my TL. I checked the underhood fuse box and found that fuse 15/Back Up/ACC had a draw on it. I narrowed it down to the interior fuse 7, which reads as this in the shop manual:

Not sure of the best way to move forward from here. It probably isn't the MICU if the drain is only on fuse 7, or could that still be a possibility? Thanks.

 

It tells you what is feed by that fuse, so simply start unplugging stuff to narrow down ever further. I would start with clock, then XM receiver, then power window switch (pass and driver).

 

Disconnect the HFL/Bluetooth unit first, then check the draw.

The largest ignition-off electrical drains are a defective HFL (measured when the car has been turned off for an hour, as the HFL is designed to stay live for a half hour after ignition-off), then a bad AC relay.

 

Thanks. The HFL has been disconnected. The A/C relay didn't have an impact on the draw when I pulled it.

 

Thanks. I didn't know if there was a particular item in the list that was commonly troublesome.

 

Mine was the pw master switch, can't remember the draw, but drained the battery in a couple days.
Takes time to isolate the culprit.

 

Thanks. Sold the car before I was able to pin down the cause, but gave the new owner a heads-up on where to look.

 

If my power windows are working, I can rule out the pw master switch as the culprit for my parasitic drain, correct? Or can things be functioning properly (seemingly) and still be the cause of the drain?