i have a parasitic battery drain in a 2012 lexus, is250c. so far, narrowed it down to the #7 fuse (10A) on the passenger side, engine compartment fuse. it controls among other things i guess is, the key fob used to open the doors and trunk, gas filler door, and trunk latch. Lexus dealer has not found prob yet.

 

Can you disable the SmartKey functionality on the IS250?
That draws quite a bit of current if you have the fob near the car.
How much current is being drawn through that fuse?

 

I’m having problems with these exact 4 fuses, none of them are currently getting power when checking with a circuit reader, I checked the 20a D/C cut and it also is getting power

 

LS430 if the D/C cut fuse both sides have power and not getting to the passenger side fuse box there is either a connector unplugged or broke wire. Another thought here is it is difficult to find a good ground for your test meter at that fuse box. Make sure you have a good ground in testing to make sure voltage is not there. As you can see from the diagram it is a direct path to that fuse box through connectors. What I would do at this point is disconnect the battery and put multimeter on ohms and see if there is a short at fuse box. If no short hook battery back up and trace wire backwards to find open or simply put a wire from the fused side of D/C cut fuse to that point. This is the diagram I would be looking at to help you.