2008 Mazda Other mazda cx-9 evaporator core

This involves way more than one diagram. You need a copy of the manufacturer's service manual. That will have many pages of instructions with numerous line drawings, and a page of special tools needed. Don't waste your money on Haynes or Chiltons manuals. Those only cover things that can be done by competent do-it-yourselfers, and this is not one of those jobs. You can also go to the top of this page, point to "Repair and Service", then click on "Manuals" to be taken to a web site where you can buy a subscription for your car from one of the services repair shops subscribe to each year.

Be aware you'll need special equipment to recover any refrigerant, and to leak-check and recharge the system. Refrigerant is extremely dangerous to work with too. Professionals wear safety glasses and gloves because it can cause frostbite and blindness. Most also wear a face shield.