Got a parasitic draw on my 2009 Civic. Today, light tested it to a fuse that's described by the owner's manual as "Backup" in slot 23 under the hood. a 10w fuse.

removed the fuse, the draw went away. Now, none of the doors will lock, so I assume that backup just means door locks? or security? as neither work now.

Since my draw is in this circuit somewhere, where should I look for the failure?

I hit a couple of jackrabbits awhile back, and lost my wheel well covers for the front on both sides. I have no idea where the wires would run for this system, so I'm hoping to avoid a high mechanical cost by narrowing it down and trying to do it myself. Thanks in advance for your response!

 

The backup fuse powers a bunch of things, many of which normally draw a small amount of power when the car is off.

- Clock
- Station memory in radio
- Code memory in ECU, ABS, etc computers
- Keyless / anti-theft system

The biggest cause of real parasitic draw are aftermarket sound systems and the light in the trunk.

You can see if it is even parasitic draw at all by disconnecting the battery while parked. If the battery is again dead when you come back it is the battery itself that is the problem, either running itself down or not being charged. This test is safe to do on older models. I'm not sure about a 2009, there may be things that need dealer intervention after the battery has been disconnected for long.