A lot of items are associated with "backup" fuse ......and little to no service info available for free on 9ths.

Do you have young children ? (if coins get slid into the CD slot it can trigger a drain)

 

Coins in c/d is a good one Craig.
OP:
When did this problem start?
Do you have any after market accessories?
Has the car been wrecked/repaired?

Here's a list of items that are connected to fuse A29.
Under-Hood Fuse/Relay Box (A)
Fuse A29 10A.

Audio-navigation unit,
Audio unit,
Automatic lighting control unit*6,
Automatic lighting control unit/sensor*7,
Data link connector,
Gauge control module (speedo),
Gauge control module (tach),
HandsFreeLink control unit,
Immobilizer-keyless control unit*1,
Information display unit,
Keyless access control unit*2,
MICU (+B_BACK_UP),
Multi-information display unit,
Power window master switch

*1: Without keyless access system
*2: With keyless access system
*3: '12 model
*4: '13-15 models
*5: Natural gas models
*6: '12 model with automatic lighting
*7: '13-15 models with automatic lighting

 

I have a 3YO that likes to pretend shes driving, but I don't think she put anything in the CD slot.

I don't know exactly when the issue started. I had a dead battery about 3 months ago, purchased a new battery, no issues for a few days, then the new battery died overnight. After that I discovered the fuse issue. No aftermarket accessories, unless you count a radar detector and a dash cam? I am the original owner, 150K.

Today my check charging system alert popped up while I was on the freeway going about 70. Volt meter was reading 11.2, accelerated to 80, volts dropped to 9.2V, then every check alert displayed on the imid and my lights dimmed enough that other drivers thought they were off. When I let off the gas and coasted the voltage slowly creeped back up to 12V, after 20 minutes of conservative driving, I started seeing 14.2V. So it looks like this battery is taking a dive!

 

Sounds to my amateur ear like a bad alternator (alternator diode), otherwise you'd have a voltage increase with acceleration.

 

Anyone ever figure this one out? Having the same issue

 

Fuse #29 (backup) for DLC (obd2) also
You should scanning your car and show what DTC appears

 

For me it ended up being a Passenger door lock switch staying on constantly causing the car to stay awake,