In NJ is a used car dealer required to disclose all accidents the car may have benn involved in? Especially if there was damage?
At most they would be required to disclose those they know of. Since it is a used car someone else had it and if they did not inform the dealer, the dealer likely would not know and can’t be required to disclose what they don’t know.
If the damage was sever enough, ther might be some tell-tale signs of it, like mis-matched paint or overspray onto other components. Aftermarket parts can be different than original equipment, too. A used car dealer should know the difference. If the dealer says “no one told us of any”, then you might ask what their close inspection shows.
Check with your state’s DMV or Atty General’s Office of Consumer Affairs.
Most state’s have very specific statutes dealing with used car transactions, and they can be different for dealers than for individuals.