Nissan

My girlfriends 2017 nissan sentra hvac will only blow out dash vents. I changed out the mode door motor but didnt fix it. So I took it to nisson of silsbee in texas. They told me they would diagnose it for $186 but when they found the box the mode motor came in they called me. I told them I had changed the mode door motor with one I had bought from them. They said they would still diagnose it but would charge $300 and something. I dont think it should cost more because it has been worked on before.