Girlfriend just got a car (not honda) just figured id ask to see if icould pointed in the right direction. Car seems to shake lightly at idle but with ac on it shakes pretty bad and seems to make a screechy noise sounds like coming from alternator area? Also the ac will work with engine off but heater doesn't and with engine on ac does not seem to work. Thanks for any help

 

Check the engine mounts for cracks. Also check condition of the AC belt. Do you hear the compressor engaging when the AC is on?

 

I'll check the mounts. Ac seems to work while engine is off and blows pretty cold but didn't check to hear compressor. Ac does not work while engine is on but ican hear something under the hood make a sort of screech noise but not sure it is the compressor I'll check that also thanks