Is a RV repair Garage responsible/liable for damage to customer property while on business property ?

In general the answer would be yes, leaving your vehicle created a bailment and duties of care in the garage/dealership or repair facility. But, most if not all authorized service facilities utilize repair orders that contain language protecting them from just this sort of problem. Certainly there are exceptions and you should have a local atty. look at the repair orders you signed upon dropping off your vehicle and any other documentation if any. Your local state agency overseeing repair facilities is also a good source of information.

Mike is right that the general rule is that the garage is liable and also right that many garages try to avoid that liability by sneaking into their paperwork a small print clause that tries to deny any responsibility, but that may not be enforceable. You should talk to a consumer law attorney near you about your state laws, including bailment, breach of contract and your state's "Udap" law (which is a consumer protection law). Call your local atorney bar association and ask for a referral to a consumer law attorney. Or you can look for one on this web site's free 50 state list of consumer law lawyers (they don't pay to be listed here and most are members of the only national organization of consumer law lawyers, www.naca.net: http://www.ohiolemonlaw.com/ocll-site/ocll-locate_local.shtml