The dealer is not required to give you the carfax at all, or any other similar vehicle history report. But it never hurts to ask for it. You can also get it online yourself at www.carfax.com but it will cost you a modest fee. Of course, the time to look at a vehicle history report is before you buy the vehicle, although you can still get a better understanding of the vehicle's condition and history by "pulling" a report yourself. Keep in mind, however, that none online vehicle history report is totally accurate and complete. Not every state reports its data and not every insurance company reports its data either. Carfax and AutoCheck, etc, are private companies providing what data they have been able to obtain and it may not always be accurate. And a vehicle history report will tell you almost nothing if the vehicle is still new so it's really only useful for a used vehicle purchase consideration. Before you decide to buy a used car read this Avvo.com guide on How to Avoid Buying a Lemon Used Car in 7 Steps: http://www.avvo.com/legal-guides/ugc/how-to-avoid-buying--lemon-used-car-in-7-steps. Once you have already spent your money, it's not too late to have an independent repair shop inspect it and tell you what they think, but the best time is before you put down your hard earned money. Once you have already bought it, generally your legal rights in a used car sale depend on what your sales paperwork says. Still, there are exceptions to every rule, including that one. You need to talk to a local Consumer Law attorney who deals with this kind of case. Call your local attorney's Bar Association and ask for a referral to a Consumer Law attorney near you or you can go to this web site page for a Free Online 50 State National List of Consumer Law Lawyers (http://www.ohiolemonlaw.com/ocll-site/ocll-locate_local.shtml) and find one near you (lawyers don’t pay to get listed here and most of them are members of the only national association for Consumer Law lawyers, NACA.net). But act quickly because for every legal right you have, there is only a limited amount of time to actually file a lawsuit in court or your rights expire (it's called the statute of limitations), so don't waste your time getting to a Consumer Law attorney and finding out what your rights are. If this answer was helpful, please give me a “thumbs up” below.
Since you are asking about a carfax report, I'm assuming you have discovered a prior accident or other damage that the dealer didn't tell you about. Even though you may have had no reason to know this beforehand, you still may have a legal cause of action. This is particularly true if your vehicle came with a warranty. I suggest you contact an experienced consumer protection attorney in Texas to review your documents. You should be able to get a free consultation to determine if fraud may have occurred, or a violation of your local UDAP statute. Try www.naca.net to find a good lawyer.