Nissan Repair: A/C, proper parameters, sight glass

Question
Can I check the a/c to see if it needs refrigerant

Answer
Hi Greg -

What is the make and model of your vehicle?

Usually low refrigerant can be detected by bubbles in the sight glass, located along the high pressure side of the system. However the best way is to connect a manifold to the system, and then compare pressures with proper parameters (check with your local dealer and tell him the make and model). Always fill refrigerant from the low side.

Hope this helps -
aloha
calvin