Battery drains after sitting one hour with doors left unlocked

We need to figure out what is staying on and how large the draw is when the vehicle is left unlocked.

I suspect this has nothing to do with the actual locking system, it has to do with when you lock the vehicle you are triggering the body control module to send the sleep command for all the modules and they shut off. When you are leaving it unlocked, the modules are supposed to time out as well but clearly on or multiples are not and it is keeping the bus awake which is draining your battery.

Let's hook a meter inline to the negative battery cable and monitor how many amps there are when you leave the doors unlocked and if it drops after 10 minutes. Clearly when you first shut the engine off, most all modules stay awake so we need to wait about 10 minutes to allow the modules to go to sleep normally. One we see what the draw is after this we can try to figure out what modules are staying awake when they should be asleep.

Does this make sense?

Hi,

What you need to do is check to see which circuit is drawing the power. For example, if you remove the fuse for the power door locks, does the battery drain out?

Here is a link that explains how to check for a draw. It indicates that the battery drains overnight, but it is the same principal.

https://www.2carpros.com/articles/car-battery-dead-overnight

If you find that removing the fuse for the door locks prevents the battery drain, we will need to check each of the actuators one at a time to determine which one is causing the issue. One may not be fully engaging and causing the draw.

Also, see if you can notice any humming noise (will be slight) from any of the doors.

Let me know.
Joe

Unfortunately we need to use a meter. The test light method relies on you telling the brightness of the bulb changing. If it doesn't go off we assume the issue never changed. A meter will tell us when the amperage changes when unplugging a fuse.

As for the body control module, this is just like the brain of the vehicle and tells all others what to do. I would suggest we use a meter to do this test and go from there.

Hi,

Is the module what was causing the battery drain?

Joe

That's good news. I'm glad to hear it's fixed. If we were of any help, you are very welcome.

Take care of yourself and feel free to come back anytime in the future if you need help or simply have a question.

Joe