[It's a Kia]

Do a search here on this forum. I got into a long discussion with a poster about his liftgate. I listed a lot of questions for him. Come back post the questions I asked him with your answers and I will try to help. I explain to him using the correct terms is important so we are all on the same page. Master Lock makes padlocks so I have no idea what you actually mean. I am an automotive locksmith. We eventually got his issue figured out. Turned out there wasn't anything wrong with his. I also don't see your model level listed. They usually lock the discussion if you haven't filled all your info in. If they lock it just fill your info into your account and "I think" they reopen it. If not just repost and I will look for it. Maybe we can get yours figured out.

 

[It's a Kia]

Wow. That's an odd issue. It would require some testing. You would need a wiring diagram for the latch. Basically what you want to test is if the latch is receiving the unlock command from the drivers door switch. Since it unlocks with the fob it makes it an interesting puzzle. Without testing my first guess would be a switch issue and my second guess would be a wiring issue. I would also need to know which wire unlocks the latch from the fob. Lot's of moving parts here.

Do you happen to have a bidirectional programmer? There is probably a data PID to unlock the hatch. I would be curious to see what that does. The other problem on these at least on the auto open and close models is I "think" the open close sensor is in one of the lift arms and not in latch as I wrongly assumed on my own SX. Usually on things like this you would be able to keep the liftgate open and close the latch to do testing while it's open. Because the sensor is in the lift arms it's not easy to test.

 

[It's a Kia]

I was thinking more about this and didn't want this post lost in my previous post.

These vehicles have become overly complicated. Even more reason a wiring a diagram is needed. This circuit might go through the fuse box which they call a smart box or something like that and it has non replaceable (according to Kia but there's always a way) relays. Does it go through that? After that does it go the the BCM or does it go to the BCM first than the fuse box? Does it go from the switch to the latch directly (I have my doubts on this). This is why the entire circuit needs to be tested. Say you have a power command coming out of the switch but it doesn't make it to the latch. You have to test every point, every junction on the way to see where the fault is. 99.99% of people do not have this kind of testing knowledge. What sounds so simple on modern cars isn't always the case. I am very curious if you get this figured out.

There is a data PID just for the cargo light. In order for that to happen it has to run through something like the smart fuse box and or the BCM. If it was direct the programmer couldn't differentiate what state it's in (on or off) that's why I suspect the lock/unlock is probably controlled. Please make sure to let us know as this will help a lot of people in the future.

 

[It's a Kia]

Hey, I edited my original post to add the info about the fix. It was my mistake that I forgot to mention that the back left door lock actuator broke a few weeks earlier, and the door couldn't opet from inside and outside, and a temporary fix by the car mechanic was to rewire it somehow to make it at least open from the inside. Which was fine at as we usually do not use that door often.

When he did that, the problem probably started, but we didn't notice it right away. When the new part arrived and he replaced it, the problem with the trunk not unlocking through the in-car button went away. So this "problem" will probably not be something people encounter often, if ever, however it's better to have the known solution if anyone wonders.

Thanks for your time, all the best!

Looks like I was correct about a wiring issue. lol Glad you got it sorted.