it includes warranty disputes ....
which is what the op claims
I understand that it includes warranty disputes. The problem is the Dealer holds the bond, not GM. GM, who pays the warranty claims is saying it’s not a warranted issue under the warranty that GM issued. The dealer didn’t issue the warranty.
So yes, a claim can be filed against the dealer, or dealers as multiple dealers have given the same answer, but it will be a useless claim since it is out of the dealers hands right now unless you think the dealer should just suck it up and pay for it out of their own pocket and not be reimbursed by GM just to make the customer happy. That is not always good business and the fact that the OP had already soured the relationship with that dealer, I don’t think that is likely. You will spend more in legal fees and time than if you just paid for whatever fix you think needs to be made.
I deal with warranty claims on equipment we build that costs any where from $500,000 to $4,000,000. I get it. A lot of wiggle room sometimes, but at the end of the day it comes down to the contractual requirements. When a customer is willing to work with us in a questionable issue, we are willing to see if we can find a compromise. When a customer appears to be demanding and not willing to work with us, we will hold a pretty firm line. I have authorized over $200,000 of warranty work on something that could be argued as not being warranty because of a good relationship. Sometimes we have customers offer to split the cost. I have also told customers they needed to pay for a $10,000 item because they are not willing to have a discussion or have burnt a bridge in the past.