Does he do this when you first leave your home as well? Maybe he does not like the feeling of the seatbelt because he is restrained. If he has no problem with it originally it is most likely because he does not want to leave the store. You can try some sort of reward system for being in the car seat. You have to be tough with it though so he does not get the reward if he does not do well.

We used to reward my daughter with a small toy for being good in the store. She is now nine and nonverbal and loves the store. We let her pick her own food items and toys and she loves the interaction. This kind of thing takes a long time to overcome because of the lack of communication.

Working with communication skills will help to using sign language, PECS, and a tablet. If the child cannot communicate their needs there is a lot of frustration.

Yes, sometimes it works. I have been trying to do a lot of my shopping when he is in preschool so I only have my 2 year old with me. He did do great at the store yesterday and getting in the car which was good since my phone was nearly dead and prob wouldn't be able to play a video.

Any luck?

That is a great idea! He loves youtube also!

My toddler is a Youtube hound so usually if we fire up Youtube on one of our phones to a video he likes, he'll completely fall into it and become like putty