right side back passenger door has a medium dent will it effect car functioning

I would check and make sure the window and locks work properly. Also make sure the door closes properly and there are no gaps around the door. You dont want water coming in if it rains and creating mold on the carpet. We perform pre-purchase inspections on vehicles before cars are performed. It is a comprehensive inspection of a check list of brakes, suspension, electrical, mechanical inspections. This way, you know what you are buying and related issues you may have. I will say, most people are surprised at what we find and thank us in the end. We save them from making a bad purchase or give them negotiating room with the buyer. Let us know if we can be of ant help. Auto Lab Troy 248-643-7690