I bought a used 2018 Elantra. A few months after getting it, it wouldn't start one morning. I got it started but was surprised that I had left nothing on. It happened again so I brought it to the dealership. They found nothing and charged me $150 for the "checks" and to charge the battery fully.

I tested battery draw with the vehicle off, door switch overriden, interior light fuse pulled and it was 1.5 Amps. I went through the fuses and was able to drop the current draw by 1.1 when I pulled the multimedia fuse, another 0.14 amps if I pulled the Memory 1 10amp fuse and another 0.11 amp if I unplugged the inside fuse panel altogether. Leaving 0.15 amps. I am going to try to leave the multimedia fuse out and see how I do.

What should be my next steps? I haven't found a circuit diagram that shows the power very well. Do I have to swap the Multimedia system out?

Thanks.

 

Unfortunately, when you pull a fuse on some areas that might producing a parasitic drain and reinstall the fuse the problem can do a reset and the drain no longer appears.

The better way to pin down a drain is to first, allow all modules to go into sleep mode, can take up to 45 minutes on some vehicles. Then, measure the voltage drop across each fuse. The circuit with the highest voltage drop is the one that we start looking into. That way nothing has a chance to reset and make us think we found the problem..

 

When I pull the fuse the current drops, when I put it back in the current goes back up. I will try leaving the car for longer next time to make sure everything goes to sleep.

I don't understand measuring the voltage drop accross a fuse, won't it always be very close to zero? How do you get access to the fuse leads when the fuse is installed?

Thanks!

 

You are right. The reading is very low and is measured in millivolts.
If you look closely , the top of each fuse should have a small opening to check with a pointed probe. There is a small opening over each leg.