Q: While driving on highway, van door independently opened

The rear sliding door on my minivan has been continual headaches! I purchased the vehicle used and the passenger door started opening while I was driving. When I stopped to get gasoline one night, a passenger got out and the door fell off! I took it to the dealership for repair. Then, the driver’s side started opening while the van was in motion, driving. That was a few months after the other door had fallen off. Back to the driver’s side door, which happened one night while I was on a busy highway. When it independently opened, I pulled over to the shoulder and the door fell off while trying to close it. I went back to the dealership and got that door repaired. Now, the passenger side door has started independently opening again while I’m driving and the dealership will have to repair it too. This is a very dangerous situation because I usually have kids in the van with me. Do you know if there is any permanent way to fix these doors so this will stop happening?