Sliding door will not stay shut

When the door unlatches does it appear to be just the rear? If it is the rear then most likely the latch at the back of the door is not holding. Take a screw driver and flip the latch closed and spray it down with a spray lubricant. Then pull the outside door handle and it will release the latch. Do this about 10 times and try to close it again.

If the whole door pops open then it may be a pressure sensor in the latch that is telling it to reverse. However, the most common cause of these is an obstruction (or a perceived obstruction created from resistance) and it reverses. I would spray down the upper and lower tracks to make sure they are sliding easily.

If none of this does the trick, get a video of the door and what it is doing so we can see as well. Thanks

Okay. I understand that is frustrating but of the issues that can cause this that is the best of them. The door ajar switch for that door is on that side of the door so that makes sense that it causes the door ajar switch to trip. However, that is normally always caused by that rear latch. If you open the door all the way and then look from the rear, you will see the latch. Just operate it as I said and spray it down and I bet you will be good to go.

Keep us updated. Thanks

That really helped. Thanks for that.

The rear latch is not pulling the door in. It actually has two steps. The first step is the latch will "grab" the striker. The second is the latch motor pulls the door shut and gets to full latched.

I want you to try something if you would.

When the door gets almost closed and the latch is about the grab the striker, press it in with your hand. Just put consistent pressure on the door over the latch. Don't jam it in there just put pressure on it like you are helping your child into the van. You don't want to throw the kid in there, just help them step in. Same thing, you just want to help it close. I am wondering if you put pressure on it, will the latch motor be able to pull the door in and get to the final latch (or full latch) position?

So what it appears is that with no help from you, it does not latch at all and can slide open when driving and with assistance from you it achieves the half latch position but never fully latches, correct?

If this is the case then the issue appears to be the "closer motor" cannot pull the door in and achieve the full latch position. I attached the detail about how the rear latch works. Take a look at it and let me know what questions you have.

I understand that you replaced this a little while ago, but unfortunately new parts are not good parts.

Is there any chance you have a scan tool that can monitor the switch in the latch? If you do, I would suspect you will find that it never achieves the full latch status which means the motor is not able to do it. If there was a sensor or something wrong with the closing system it would actually reverse the door and open it at least partially but that is not what this is doing it. It is just leaving it popped open so none of the sensors are seeing an issue in order to constitute a reversal.

Hopefully there was a part warranty with that assembly because if it were me, I would replace the rear assembly.

Okay. All good points. As you said, I think the issue you are having rests in the operation of the latch. The best way I can describe it is the latch has two stages. Half latched is the first stage. This is where the door motor slides the door forward and the tracks guide the door in so that the front and rear latches make contact with the strikers which are the hooks on the body of the vehicle. When they make contact there is a switch that is flipped to tell the latch motor to move from the open position to the half latched position. This is means it closes the latch around the striker. Then it begins to move to the second position which is the fully latched position. To do this, the motor closes the latch even more and this action actually pulls the door in the rest of the way and locks it closed.

The fact that it is beginning to close shows the motor can grab the striker but is not able to pull the door in. The reason is, the motor is either weak or the assembly is binding.

Here is a video of someone dealing with the same thing:

https://youtu.be/KMoDrTaC3bQ

Keep in mind the testing that he did on the motor is not actually a test. He just removed it and put power to it. So he didn't fix anything and I am sure when he put it back in it stopped working then or shortly after.

As for just doing the motor, I was not able to find one with just the motor at any of the major parts sites. It appears they only come as an assembly but you could look at a used one if you want to. Also, what was the reason you replaced the assembly before? Is the motor okay on the other unit you had laying on the garage floor? If so, just swap that motor onto this assembly.

I would definitely call the dealer where you bought it and tell them what happened and that it failed the same way. I would be surprised if they didn't at least cover part of it for you. If they don't give you a deal or cover it, then I would call the OEM directly as it was their part and not the dealers. Clearly these are meant to last longer then that. I work for a different OEM and this is a situation that we would consider what is called "goodwill."

Basically we have a customer that had many different options but went with an OEM part and it failed in a year and a month outside the part warranty. If this went across my desk, I would authorize the replacement.

Clearly there could be another issue but based on everything I am seeing the motor is the issue. It is unlikely for this to happen but unfortunately I see it often where a new part fails. I have learned that new parts are not "good" parts.