My son has a check written out to him. I also have an account in the same Bank. I also have access to his account.
Can I deposit the check in my account?
My son lives in California
If your son endorses the check or better still, endorses it with "for deposit only" and places the account number in the endorsement, it's likely the bank will accept it for deposit. In this manner, you are not putting it in your account, you are putting it in his. I have a family member perform this action occasionally with zero complications and she does not have an account at the same bank.
If the check is made out to him, he will have to endorse it. Which means that at some point he will have to physically have the check in his hands. At which point, he could probably just deposit it himself.
If there's some problem getting the check to him for him to sign it, you could call the bank and ask if they'll accept it for deposit to his account without a signature. I understand some banks will do this. I would be very surprised if they would let you deposit a check made out to your son to your account. They'd have no way of knowing if your son was agreeable to this or if you were stealing his money.
Traditionally, the person the check was made out to could endorse it, give the check to someone else, and then the second person could endorse it and deposit it to their (the second person's) account. That is, the endorsement would have your son's signature, and below that, your signature. But I understand some banks won't accept this any more, so you'd be best to check before trying it.
You can simply deposit the check into your joint account. You should be able do that even without his signature. Then you can transfer the money out of that account and into yours.